<?php

namespace PHPExcel;

if (!defined('CALCULATION_REGEXP_CELLREF')) {
    // Test for support of \P (multibyte options) in PCRE
    if (defined('PREG_BAD_UTF8_ERROR')) {
        // Cell reference (cell or range of cells, with or without a sheet reference)
        define('CALCULATION_REGEXP_CELLREF', '((([^\s,!&%^\/\*\+<>=-]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?\$?([a-z]{1,3})\$?(\d{1,7})');
        // Named Range of cells
        define('CALCULATION_REGEXP_NAMEDRANGE', '((([^\s,!&%^\/\*\+<>=-]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?([_A-Z][_A-Z0-9\.]*)');
    } else {
        // Cell reference (cell or range of cells, with or without a sheet reference)
        define('CALCULATION_REGEXP_CELLREF', '(((\w*)|(\'[^\']*\')|(\"[^\"]*\"))!)?\$?([a-z]{1,3})\$?(\d+)');
        // Named Range of cells
        define('CALCULATION_REGEXP_NAMEDRANGE', '(((\w*)|(\'.*\')|(\".*\"))!)?([_A-Z][_A-Z0-9\.]*)');
    }
}

/**
 * \PHPExcel\Calculation (Multiton)
 *
 * Copyright (c) 2006 - 2015 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * @category PHPExcel
 * @package PHPExcel_Calculation
 * @copyright Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt LGPL
 * @version ##VERSION##, ##DATE##
 */
class Calculation {
    /**
     * Constants
     */
    /**
     * Regular Expressions
     */
    // Numeric operand
    const CALCULATION_REGEXP_NUMBER = '[-+]?\d*\.?\d+(e[-+]?\d+)?';
    // String operand
    const CALCULATION_REGEXP_STRING = '"(?:[^"]|"")*"';
    // Opening bracket
    const CALCULATION_REGEXP_OPENBRACE = '\(';
    // Function (allow for the old @ symbol that could be used to prefix a function, but we'll ignore it)
    const CALCULATION_REGEXP_FUNCTION = '@?([A-Z][A-Z0-9\.]*)[\s]*\(';
    // Cell reference (cell or range of cells, with or without a sheet reference)
    const CALCULATION_REGEXP_CELLREF = CALCULATION_REGEXP_CELLREF;
    // Named Range of cells
    const CALCULATION_REGEXP_NAMEDRANGE = CALCULATION_REGEXP_NAMEDRANGE;
    // Error
    const CALCULATION_REGEXP_ERROR = '\#[A-Z][A-Z0_\/]*[!\?]?';
    
    /**
     * constants
     */
    const RETURN_ARRAY_AS_ERROR = 'error';
    const RETURN_ARRAY_AS_VALUE = 'value';
    const RETURN_ARRAY_AS_ARRAY = 'array';
    private static $returnArrayAsType = self::RETURN_ARRAY_AS_VALUE;
    
    /**
     * Instance of this class
     *
     * @access private
     * @var \PHPExcel\Calculation
     */
    private static $instance;
    
    /**
     * Instance of the spreadsheet this Calculation Engine is using
     *
     * @access private
     * @var PHPExcel
     */
    private $spreadsheet;
    
    /**
     * List of instances of the calculation engine that we've instantiated for individual spreadsheets
     *
     * @access private
     * @var \PHPExcel\Calculation[]
     */
    private static $spreadsheetSets;
    
    /**
     * Calculation cache
     *
     * @access private
     * @var array
     */
    private $calculationCache = array();
    
    /**
     * Calculation cache enabled
     *
     * @access private
     * @var boolean
     */
    private $calculationCacheEnabled = true;
    
    /**
     * List of operators that can be used within formulae
     * The true/false value indicates whether it is a binary operator or a unary operator
     *
     * @access private
     * @var array
     */
    private static $operators = array(
    '+' => true,
    '-' => true,
    '*' => true,
    '/' => true,
    '^' => true,
    '&' => true,
    '%' => false,
    '~' => false,
    '>' => true,
    '<' => true,
    '=' => true,
    '>=' => true,
    '<=' => true,
    '<>' => true,
    '|' => true,
    ':' => true 
    );
    
    /**
     * List of binary operators (those that expect two operands)
     *
     * @access private
     * @var array
     */
    private static $binaryOperators = array(
    '+' => true,
    '-' => true,
    '*' => true,
    '/' => true,
    '^' => true,
    '&' => true,
    '>' => true,
    '<' => true,
    '=' => true,
    '>=' => true,
    '<=' => true,
    '<>' => true,
    '|' => true,
    ':' => true 
    );
    
    /**
     * The debug log generated by the calculation engine
     *
     * @access private
     * @var CalcEngine\Logger
     *
     */
    private $debugLog;
    
    /**
     * Flag to determine how formula errors should be handled
     * If true, then a user error will be triggered
     * If false, then an exception will be thrown
     *
     * @access public
     * @var boolean
     *
     */
    public $suppressFormulaErrors = false;
    
    /**
     * Error message for any error that was raised/thrown by the calculation engine
     *
     * @access public
     * @var string
     *
     */
    public $formulaError = null;
    
    /**
     * An array of the nested cell references accessed by the calculation engine, used for the debug log
     *
     * @access private
     * @var array of string
     *     
     */
    private $cyclicReferenceStack;
    private $cellStack = array();
    
    /**
     * Current iteration counter for cyclic formulae
     * If the value is 0 (or less) then cyclic formulae will throw an exception,
     * otherwise they will iterate to the limit defined here before returning a result
     *
     * @var integer
     *
     */
    private $cyclicFormulaCounter = 1;
    private $cyclicFormulaCell = '';
    
    /**
     * Number of iterations for cyclic formulae
     *
     * @var integer
     *
     */
    public $cyclicFormulaCount = 1;
    
    /**
     * Epsilon Precision used for comparisons in calculations
     *
     * @var float
     *
     */
    private $delta = 0.1e-12;
    
    /**
     * The current locale setting
     *
     * @var string
     *
     */
    private static $localeLanguage = 'en_us'; // US English (default locale)
    

    /**
     * List of available locale settings
     * Note that this is read for the locale subdirectory only when requested
     *
     * @var string[]
     *
     */
    private static $validLocaleLanguages = array(
    'en' 
    ); // English (default language)

    
    /**
     * Locale-specific argument separator for function arguments
     *
     * @var string
     *
     */
    private static $localeArgumentSeparator = ',';
    private static $localeFunctions = array();
    
    /**
     * Locale-specific translations for Excel constants (True, False and Null)
     *
     * @var string[]
     *
     */
    public static $localeBoolean = array(
    'TRUE' => 'TRUE',
    'FALSE' => 'FALSE',
    'NULL' => 'NULL' 
    );
    
    /**
     * Excel constant string translations to their PHP equivalents
     * Constant conversion from text name/value to actual (datatyped) value
     *
     * @var string[]
     *
     */
    private static $excelConstants = array(
    'TRUE' => true,
    'FALSE' => false,
    'NULL' => null 
    );
    
    // PHPExcel functions
    private static $PHPExcelFunctions = array(
    'ABS' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'abs',
    'argumentCount' => '1' 
    ),
    'ACCRINT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::ACCRINT',
    'argumentCount' => '4-7' 
    ),
    'ACCRINTM' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::ACCRINTM',
    'argumentCount' => '3-5' 
    ),
    'ACOS' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'acos',
    'argumentCount' => '1' 
    ),
    'ACOSH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'acosh',
    'argumentCount' => '1' 
    ),
    'ADDRESS' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::cellAddress',
    'argumentCount' => '2-5' 
    ),
    'AMORDEGRC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::AMORDEGRC',
    'argumentCount' => '6,7' 
    ),
    'AMORLINC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::AMORLINC',
    'argumentCount' => '6,7' 
    ),
    'AND' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::logicalAnd',
    'argumentCount' => '1+' 
    ),
    'AREAS' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'ASC' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'ASIN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'asin',
    'argumentCount' => '1' 
    ),
    'ASINH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'asinh',
    'argumentCount' => '1' 
    ),
    'ATAN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'atan',
    'argumentCount' => '1' 
    ),
    'ATAN2' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::ATAN2',
    'argumentCount' => '2' 
    ),
    'ATANH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'atanh',
    'argumentCount' => '1' 
    ),
    'AVEDEV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::AVEDEV',
    'argumentCount' => '1+' 
    ),
    'AVERAGE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::AVERAGE',
    'argumentCount' => '1+' 
    ),
    'AVERAGEA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::AVERAGEA',
    'argumentCount' => '1+' 
    ),
    'AVERAGEIF' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::AVERAGEIF',
    'argumentCount' => '2,3' 
    ),
    'AVERAGEIFS' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '3+' 
    ),
    'BAHTTEXT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'BESSELI' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BESSELI',
    'argumentCount' => '2' 
    ),
    'BESSELJ' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BESSELJ',
    'argumentCount' => '2' 
    ),
    'BESSELK' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BESSELK',
    'argumentCount' => '2' 
    ),
    'BESSELY' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BESSELY',
    'argumentCount' => '2' 
    ),
    'BETADIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::BETADIST',
    'argumentCount' => '3-5' 
    ),
    'BETAINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::BETAINV',
    'argumentCount' => '3-5' 
    ),
    'BIN2DEC' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BINTODEC',
    'argumentCount' => '1' 
    ),
    'BIN2HEX' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BINTOHEX',
    'argumentCount' => '1,2' 
    ),
    'BIN2OCT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::BINTOOCT',
    'argumentCount' => '1,2' 
    ),
    'BINOMDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::BINOMDIST',
    'argumentCount' => '4' 
    ),
    'CEILING' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::CEILING',
    'argumentCount' => '2' 
    ),
    'CELL' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1,2' 
    ),
    'CHAR' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::CHARACTER',
    'argumentCount' => '1' 
    ),
    'CHIDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CHIDIST',
    'argumentCount' => '2' 
    ),
    'CHIINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CHIINV',
    'argumentCount' => '2' 
    ),
    'CHITEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'CHOOSE' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::CHOOSE',
    'argumentCount' => '2+' 
    ),
    'CLEAN' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::TRIMNONPRINTABLE',
    'argumentCount' => '1' 
    ),
    'CODE' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::ASCIICODE',
    'argumentCount' => '1' 
    ),
    'COLUMN' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::COLUMN',
    'argumentCount' => '-1',
    'passByReference' => array(
    true 
    ) 
    ),
    'COLUMNS' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::COLUMNS',
    'argumentCount' => '1' 
    ),
    'COMBIN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::COMBIN',
    'argumentCount' => '2' 
    ),
    'COMPLEX' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::COMPLEX',
    'argumentCount' => '2,3' 
    ),
    'CONCATENATE' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::CONCATENATE',
    'argumentCount' => '1+' 
    ),
    'CONFIDENCE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CONFIDENCE',
    'argumentCount' => '3' 
    ),
    'CONVERT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::CONVERTUOM',
    'argumentCount' => '3' 
    ),
    'CORREL' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CORREL',
    'argumentCount' => '2' 
    ),
    'COS' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'cos',
    'argumentCount' => '1' 
    ),
    'COSH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'cosh',
    'argumentCount' => '1' 
    ),
    'COUNT' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::COUNT',
    'argumentCount' => '1+' 
    ),
    'COUNTA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::COUNTA',
    'argumentCount' => '1+' 
    ),
    'COUNTBLANK' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::COUNTBLANK',
    'argumentCount' => '1' 
    ),
    'COUNTIF' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::COUNTIF',
    'argumentCount' => '2' 
    ),
    'COUNTIFS' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'COUPDAYBS' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPDAYBS',
    'argumentCount' => '3,4' 
    ),
    'COUPDAYS' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPDAYS',
    'argumentCount' => '3,4' 
    ),
    'COUPDAYSNC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPDAYSNC',
    'argumentCount' => '3,4' 
    ),
    'COUPNCD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPNCD',
    'argumentCount' => '3,4' 
    ),
    'COUPNUM' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPNUM',
    'argumentCount' => '3,4' 
    ),
    'COUPPCD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::COUPPCD',
    'argumentCount' => '3,4' 
    ),
    'COVAR' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::COVAR',
    'argumentCount' => '2' 
    ),
    'CRITBINOM' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CRITBINOM',
    'argumentCount' => '3' 
    ),
    'CUBEKPIMEMBER' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBEMEMBER' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBEMEMBERPROPERTY' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBERANKEDMEMBER' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBESET' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBESETCOUNT' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUBEVALUE' => array(
    'category' => Calculation\Categories::CATEGORY_CUBE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '?' 
    ),
    'CUMIPMT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::CUMIPMT',
    'argumentCount' => '6' 
    ),
    'CUMPRINC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::CUMPRINC',
    'argumentCount' => '6' 
    ),
    'DATE' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DATE',
    'argumentCount' => '3' 
    ),
    'DATEDIF' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DATEDIF',
    'argumentCount' => '2,3' 
    ),
    'DATEVALUE' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DATEVALUE',
    'argumentCount' => '1' 
    ),
    'DAVERAGE' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DAVERAGE',
    'argumentCount' => '3' 
    ),
    'DAY' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DAYOFMONTH',
    'argumentCount' => '1' 
    ),
    'DAYS360' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DAYS360',
    'argumentCount' => '2,3' 
    ),
    'DB' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::DB',
    'argumentCount' => '4,5' 
    ),
    'DCOUNT' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DCOUNT',
    'argumentCount' => '3' 
    ),
    'DCOUNTA' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DCOUNTA',
    'argumentCount' => '3' 
    ),
    'DDB' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::DDB',
    'argumentCount' => '4,5' 
    ),
    'DEC2BIN' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::DECTOBIN',
    'argumentCount' => '1,2' 
    ),
    'DEC2HEX' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::DECTOHEX',
    'argumentCount' => '1,2' 
    ),
    'DEC2OCT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::DECTOOCT',
    'argumentCount' => '1,2' 
    ),
    'DEGREES' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'rad2deg',
    'argumentCount' => '1' 
    ),
    'DELTA' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::DELTA',
    'argumentCount' => '1,2' 
    ),
    'DEVSQ' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::DEVSQ',
    'argumentCount' => '1+' 
    ),
    'DGET' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DGET',
    'argumentCount' => '3' 
    ),
    'DISC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::DISC',
    'argumentCount' => '4,5' 
    ),
    'DMAX' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DMAX',
    'argumentCount' => '3' 
    ),
    'DMIN' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DMIN',
    'argumentCount' => '3' 
    ),
    'DOLLAR' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::DOLLAR',
    'argumentCount' => '1,2' 
    ),
    'DOLLARDE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::DOLLARDE',
    'argumentCount' => '2' 
    ),
    'DOLLARFR' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::DOLLARFR',
    'argumentCount' => '2' 
    ),
    'DPRODUCT' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DPRODUCT',
    'argumentCount' => '3' 
    ),
    'DSTDEV' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DSTDEV',
    'argumentCount' => '3' 
    ),
    'DSTDEVP' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DSTDEVP',
    'argumentCount' => '3' 
    ),
    'DSUM' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DSUM',
    'argumentCount' => '3' 
    ),
    'DURATION' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '5,6' 
    ),
    'DVAR' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DVAR',
    'argumentCount' => '3' 
    ),
    'DVARP' => array(
    'category' => Calculation\Categories::CATEGORY_DATABASE,
    'functionCall' => '\\PHPExcel\\Calculation\\Database::DVARP',
    'argumentCount' => '3' 
    ),
    'EDATE' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::EDATE',
    'argumentCount' => '2' 
    ),
    'EFFECT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::EFFECT',
    'argumentCount' => '2' 
    ),
    'EOMONTH' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::EOMONTH',
    'argumentCount' => '2' 
    ),
    'ERF' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::ERF',
    'argumentCount' => '1,2' 
    ),
    'ERFC' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::ERFC',
    'argumentCount' => '1' 
    ),
    'ERROR.TYPE' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::errorType',
    'argumentCount' => '1' 
    ),
    'EVEN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::EVEN',
    'argumentCount' => '1' 
    ),
    'EXACT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'EXP' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'exp',
    'argumentCount' => '1' 
    ),
    'EXPONDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::EXPONDIST',
    'argumentCount' => '3' 
    ),
    'FACT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::FACT',
    'argumentCount' => '1' 
    ),
    'FACTDOUBLE' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::FACTDOUBLE',
    'argumentCount' => '1' 
    ),
    'FALSE' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::FALSE',
    'argumentCount' => '0' 
    ),
    'FDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '3' 
    ),
    'FIND' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::SEARCHSENSITIVE',
    'argumentCount' => '2,3' 
    ),
    'FINDB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::SEARCHSENSITIVE',
    'argumentCount' => '2,3' 
    ),
    'FINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '3' 
    ),
    'FISHER' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::FISHER',
    'argumentCount' => '1' 
    ),
    'FISHERINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::FISHERINV',
    'argumentCount' => '1' 
    ),
    'FIXED' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::FIXEDFORMAT',
    'argumentCount' => '1-3' 
    ),
    'FLOOR' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::FLOOR',
    'argumentCount' => '2' 
    ),
    'FORECAST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::FORECAST',
    'argumentCount' => '3' 
    ),
    'FREQUENCY' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'FTEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'FV' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::FV',
    'argumentCount' => '3-5' 
    ),
    'FVSCHEDULE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::FVSCHEDULE',
    'argumentCount' => '2' 
    ),
    'GAMMADIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::GAMMADIST',
    'argumentCount' => '4' 
    ),
    'GAMMAINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::GAMMAINV',
    'argumentCount' => '3' 
    ),
    'GAMMALN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::GAMMALN',
    'argumentCount' => '1' 
    ),
    'GCD' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::GCD',
    'argumentCount' => '1+' 
    ),
    'GEOMEAN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::GEOMEAN',
    'argumentCount' => '1+' 
    ),
    'GESTEP' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::GESTEP',
    'argumentCount' => '1,2' 
    ),
    'GETPIVOTDATA' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2+' 
    ),
    'GROWTH' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::GROWTH',
    'argumentCount' => '1-4' 
    ),
    'HARMEAN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::HARMEAN',
    'argumentCount' => '1+' 
    ),
    'HEX2BIN' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::HEXTOBIN',
    'argumentCount' => '1,2' 
    ),
    'HEX2DEC' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::HEXTODEC',
    'argumentCount' => '1' 
    ),
    'HEX2OCT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::HEXTOOCT',
    'argumentCount' => '1,2' 
    ),
    'HLOOKUP' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::HLOOKUP',
    'argumentCount' => '3,4' 
    ),
    'HOUR' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::HOUROFDAY',
    'argumentCount' => '1' 
    ),
    'HYPERLINK' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::HYPERLINK',
    'argumentCount' => '1,2',
    'passCellReference' => true 
    ),
    'HYPGEOMDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::HYPGEOMDIST',
    'argumentCount' => '4' 
    ),
    'IF' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::statementIf',
    'argumentCount' => '1-3' 
    ),
    'IFERROR' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::IFERROR',
    'argumentCount' => '2' 
    ),
    'IMABS' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMABS',
    'argumentCount' => '1' 
    ),
    'IMAGINARY' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMAGINARY',
    'argumentCount' => '1' 
    ),
    'IMARGUMENT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMARGUMENT',
    'argumentCount' => '1' 
    ),
    'IMCONJUGATE' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMCONJUGATE',
    'argumentCount' => '1' 
    ),
    'IMCOS' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMCOS',
    'argumentCount' => '1' 
    ),
    'IMDIV' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMDIV',
    'argumentCount' => '2' 
    ),
    'IMEXP' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMEXP',
    'argumentCount' => '1' 
    ),
    'IMLN' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMLN',
    'argumentCount' => '1' 
    ),
    'IMLOG10' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMLOG10',
    'argumentCount' => '1' 
    ),
    'IMLOG2' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMLOG2',
    'argumentCount' => '1' 
    ),
    'IMPOWER' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMPOWER',
    'argumentCount' => '2' 
    ),
    'IMPRODUCT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMPRODUCT',
    'argumentCount' => '1+' 
    ),
    'IMREAL' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMREAL',
    'argumentCount' => '1' 
    ),
    'IMSIN' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMSIN',
    'argumentCount' => '1' 
    ),
    'IMSQRT' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMSQRT',
    'argumentCount' => '1' 
    ),
    'IMSUB' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMSUB',
    'argumentCount' => '2' 
    ),
    'IMSUM' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::IMSUM',
    'argumentCount' => '1+' 
    ),
    'INDEX' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::INDEX',
    'argumentCount' => '1-4' 
    ),
    'INDIRECT' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::INDIRECT',
    'argumentCount' => '1,2',
    'passCellReference' => true 
    ),
    'INFO' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'INT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::INT',
    'argumentCount' => '1' 
    ),
    'INTERCEPT' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::INTERCEPT',
    'argumentCount' => '2' 
    ),
    'INTRATE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::INTRATE',
    'argumentCount' => '4,5' 
    ),
    'IPMT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::IPMT',
    'argumentCount' => '4-6' 
    ),
    'IRR' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::IRR',
    'argumentCount' => '1,2' 
    ),
    'ISBLANK' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isBlank',
    'argumentCount' => '1' 
    ),
    'ISERR' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::IS_ERR',
    'argumentCount' => '1' 
    ),
    'ISERROR' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::IS_ERROR',
    'argumentCount' => '1' 
    ),
    'ISEVEN' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isEven',
    'argumentCount' => '1' 
    ),
    'ISLOGICAL' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isLogical',
    'argumentCount' => '1' 
    ),
    'ISNA' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isNa',
    'argumentCount' => '1' 
    ),
    'ISNONTEXT' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isNonText',
    'argumentCount' => '1' 
    ),
    'ISNUMBER' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isNumber',
    'argumentCount' => '1' 
    ),
    'ISODD' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isOdd',
    'argumentCount' => '1' 
    ),
    'ISPMT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::ISPMT',
    'argumentCount' => '4' 
    ),
    'ISREF' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'ISTEXT' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::isText',
    'argumentCount' => '1' 
    ),
    'JIS' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'KURT' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::KURT',
    'argumentCount' => '1+' 
    ),
    'LARGE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::LARGE',
    'argumentCount' => '2' 
    ),
    'LCM' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::LCM',
    'argumentCount' => '1+' 
    ),
    'LEFT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::LEFT',
    'argumentCount' => '1,2' 
    ),
    'LEFTB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::LEFT',
    'argumentCount' => '1,2' 
    ),
    'LEN' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::STRINGLENGTH',
    'argumentCount' => '1' 
    ),
    'LENB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::STRINGLENGTH',
    'argumentCount' => '1' 
    ),
    'LINEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::LINEST',
    'argumentCount' => '1-4' 
    ),
    'LN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'log',
    'argumentCount' => '1' 
    ),
    'LOG' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::logBase',
    'argumentCount' => '1,2' 
    ),
    'LOG10' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'log10',
    'argumentCount' => '1' 
    ),
    'LOGEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::LOGEST',
    'argumentCount' => '1-4' 
    ),
    'LOGINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::LOGINV',
    'argumentCount' => '3' 
    ),
    'LOGNORMDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::LOGNORMDIST',
    'argumentCount' => '3' 
    ),
    'LOOKUP' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::LOOKUP',
    'argumentCount' => '2,3' 
    ),
    'LOWER' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::LOWERCASE',
    'argumentCount' => '1' 
    ),
    'MATCH' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::MATCH',
    'argumentCount' => '2,3' 
    ),
    'MAX' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MAX',
    'argumentCount' => '1+' 
    ),
    'MAXA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MAXA',
    'argumentCount' => '1+' 
    ),
    'MAXIF' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MAXIF',
    'argumentCount' => '2+' 
    ),
    'MDETERM' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MDETERM',
    'argumentCount' => '1' 
    ),
    'MDURATION' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '5,6' 
    ),
    'MEDIAN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MEDIAN',
    'argumentCount' => '1+' 
    ),
    'MEDIANIF' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2+' 
    ),
    'MID' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::MID',
    'argumentCount' => '3' 
    ),
    'MIDB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::MID',
    'argumentCount' => '3' 
    ),
    'MIN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MIN',
    'argumentCount' => '1+' 
    ),
    'MINA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MINA',
    'argumentCount' => '1+' 
    ),
    'MINIF' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MINIF',
    'argumentCount' => '2+' 
    ),
    'MINUTE' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::MINUTEOFHOUR',
    'argumentCount' => '1' 
    ),
    'MINVERSE' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MINVERSE',
    'argumentCount' => '1' 
    ),
    'MIRR' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::MIRR',
    'argumentCount' => '3' 
    ),
    'MMULT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MMULT',
    'argumentCount' => '2' 
    ),
    'MOD' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MOD',
    'argumentCount' => '2' 
    ),
    'MODE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::MODE',
    'argumentCount' => '1+' 
    ),
    'MONTH' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::MONTHOFYEAR',
    'argumentCount' => '1' 
    ),
    'MROUND' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MROUND',
    'argumentCount' => '2' 
    ),
    'MULTINOMIAL' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::MULTINOMIAL',
    'argumentCount' => '1+' 
    ),
    'N' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::N',
    'argumentCount' => '1' 
    ),
    'NA' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::NA',
    'argumentCount' => '0' 
    ),
    'NEGBINOMDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::NEGBINOMDIST',
    'argumentCount' => '3' 
    ),
    'NETWORKDAYS' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::NETWORKDAYS',
    'argumentCount' => '2+' 
    ),
    'NOMINAL' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::NOMINAL',
    'argumentCount' => '2' 
    ),
    'NORMDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::NORMDIST',
    'argumentCount' => '4' 
    ),
    'NORMINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::NORMINV',
    'argumentCount' => '3' 
    ),
    'NORMSDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::NORMSDIST',
    'argumentCount' => '1' 
    ),
    'NORMSINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::NORMSINV',
    'argumentCount' => '1' 
    ),
    'NOT' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::NOT',
    'argumentCount' => '1' 
    ),
    'NOW' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DATETIMENOW',
    'argumentCount' => '0' 
    ),
    'NPER' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::NPER',
    'argumentCount' => '3-5' 
    ),
    'NPV' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::NPV',
    'argumentCount' => '2+' 
    ),
    'OCT2BIN' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::OCTTOBIN',
    'argumentCount' => '1,2' 
    ),
    'OCT2DEC' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::OCTTODEC',
    'argumentCount' => '1' 
    ),
    'OCT2HEX' => array(
    'category' => Calculation\Categories::CATEGORY_ENGINEERING,
    'functionCall' => '\\PHPExcel\\Calculation\\Engineering::OCTTOHEX',
    'argumentCount' => '1,2' 
    ),
    'ODD' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::ODD',
    'argumentCount' => '1' 
    ),
    'ODDFPRICE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '8,9' 
    ),
    'ODDFYIELD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '8,9' 
    ),
    'ODDLPRICE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '7,8' 
    ),
    'ODDLYIELD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '7,8' 
    ),
    'OFFSET' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::OFFSET',
    'argumentCount' => '3-5',
    'passCellReference' => true,
    'passByReference' => array(
    true 
    ) 
    ),
    'OR' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::logicalOr',
    'argumentCount' => '1+' 
    ),
    'PEARSON' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::CORREL',
    'argumentCount' => '2' 
    ),
    'PERCENTILE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::PERCENTILE',
    'argumentCount' => '2' 
    ),
    'PERCENTRANK' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::PERCENTRANK',
    'argumentCount' => '2,3' 
    ),
    'PERMUT' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::PERMUT',
    'argumentCount' => '2' 
    ),
    'PHONETIC' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1' 
    ),
    'PI' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'pi',
    'argumentCount' => '0' 
    ),
    'PMT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PMT',
    'argumentCount' => '3-5' 
    ),
    'POISSON' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::POISSON',
    'argumentCount' => '3' 
    ),
    'POWER' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::POWER',
    'argumentCount' => '2' 
    ),
    'PPMT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PPMT',
    'argumentCount' => '4-6' 
    ),
    'PRICE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PRICE',
    'argumentCount' => '6,7' 
    ),
    'PRICEDISC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PRICEDISC',
    'argumentCount' => '4,5' 
    ),
    'PRICEMAT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PRICEMAT',
    'argumentCount' => '5,6' 
    ),
    'PROB' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '3,4' 
    ),
    'PRODUCT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::PRODUCT',
    'argumentCount' => '1+' 
    ),
    'PROPER' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::PROPERCASE',
    'argumentCount' => '1' 
    ),
    'PV' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::PV',
    'argumentCount' => '3-5' 
    ),
    'QUARTILE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::QUARTILE',
    'argumentCount' => '2' 
    ),
    'QUOTIENT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::QUOTIENT',
    'argumentCount' => '2' 
    ),
    'RADIANS' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'deg2rad',
    'argumentCount' => '1' 
    ),
    'RAND' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::RAND',
    'argumentCount' => '0' 
    ),
    'RANDBETWEEN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::RAND',
    'argumentCount' => '2' 
    ),
    'RANK' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::RANK',
    'argumentCount' => '2,3' 
    ),
    'RATE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::RATE',
    'argumentCount' => '3-6' 
    ),
    'RECEIVED' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::RECEIVED',
    'argumentCount' => '4-5' 
    ),
    'REPLACE' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::REPLACE',
    'argumentCount' => '4' 
    ),
    'REPLACEB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::REPLACE',
    'argumentCount' => '4' 
    ),
    'REPT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => 'str_repeat',
    'argumentCount' => '2' 
    ),
    'RIGHT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::RIGHT',
    'argumentCount' => '1,2' 
    ),
    'RIGHTB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::RIGHT',
    'argumentCount' => '1,2' 
    ),
    'ROMAN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::ROMAN',
    'argumentCount' => '1,2' 
    ),
    'ROUND' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'round',
    'argumentCount' => '2' 
    ),
    'ROUNDDOWN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::ROUNDDOWN',
    'argumentCount' => '2' 
    ),
    'ROUNDUP' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::ROUNDUP',
    'argumentCount' => '2' 
    ),
    'ROW' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::ROW',
    'argumentCount' => '-1',
    'passByReference' => array(
    true 
    ) 
    ),
    'ROWS' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::ROWS',
    'argumentCount' => '1' 
    ),
    'RSQ' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::RSQ',
    'argumentCount' => '2' 
    ),
    'RTD' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '1+' 
    ),
    'SEARCH' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::SEARCHINSENSITIVE',
    'argumentCount' => '2,3' 
    ),
    'SEARCHB' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::SEARCHINSENSITIVE',
    'argumentCount' => '2,3' 
    ),
    'SECOND' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::SECONDOFMINUTE',
    'argumentCount' => '1' 
    ),
    'SERIESSUM' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SERIESSUM',
    'argumentCount' => '4' 
    ),
    'SIGN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SIGN',
    'argumentCount' => '1' 
    ),
    'SIN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'sin',
    'argumentCount' => '1' 
    ),
    'SINH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'sinh',
    'argumentCount' => '1' 
    ),
    'SKEW' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::SKEW',
    'argumentCount' => '1+' 
    ),
    'SLN' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::SLN',
    'argumentCount' => '3' 
    ),
    'SLOPE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::SLOPE',
    'argumentCount' => '2' 
    ),
    'SMALL' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::SMALL',
    'argumentCount' => '2' 
    ),
    'SQRT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'sqrt',
    'argumentCount' => '1' 
    ),
    'SQRTPI' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SQRTPI',
    'argumentCount' => '1' 
    ),
    'STANDARDIZE' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STANDARDIZE',
    'argumentCount' => '3' 
    ),
    'STDEV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STDEV',
    'argumentCount' => '1+' 
    ),
    'STDEVA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STDEVA',
    'argumentCount' => '1+' 
    ),
    'STDEVP' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STDEVP',
    'argumentCount' => '1+' 
    ),
    'STDEVPA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STDEVPA',
    'argumentCount' => '1+' 
    ),
    'STEYX' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::STEYX',
    'argumentCount' => '2' 
    ),
    'SUBSTITUTE' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::SUBSTITUTE',
    'argumentCount' => '3,4' 
    ),
    'SUBTOTAL' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUBTOTAL',
    'argumentCount' => '2+' 
    ),
    'SUM' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUM',
    'argumentCount' => '1+' 
    ),
    'SUMIF' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMIF',
    'argumentCount' => '2,3' 
    ),
    'SUMIFS' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMIFS',
    'argumentCount' => '3+' 
    ),
    'SUMPRODUCT' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMPRODUCT',
    'argumentCount' => '1+' 
    ),
    'SUMSQ' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMSQ',
    'argumentCount' => '1+' 
    ),
    'SUMX2MY2' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMX2MY2',
    'argumentCount' => '2' 
    ),
    'SUMX2PY2' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMX2PY2',
    'argumentCount' => '2' 
    ),
    'SUMXMY2' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::SUMXMY2',
    'argumentCount' => '2' 
    ),
    'SYD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::SYD',
    'argumentCount' => '4' 
    ),
    'T' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::RETURNSTRING',
    'argumentCount' => '1' 
    ),
    'TAN' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'tan',
    'argumentCount' => '1' 
    ),
    'TANH' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => 'tanh',
    'argumentCount' => '1' 
    ),
    'TBILLEQ' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::TBILLEQ',
    'argumentCount' => '3' 
    ),
    'TBILLPRICE' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::TBILLPRICE',
    'argumentCount' => '3' 
    ),
    'TBILLYIELD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::TBILLYIELD',
    'argumentCount' => '3' 
    ),
    'TDIST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::TDIST',
    'argumentCount' => '3' 
    ),
    'TEXT' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::TEXTFORMAT',
    'argumentCount' => '2' 
    ),
    'TIME' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::TIME',
    'argumentCount' => '3' 
    ),
    'TIMEVALUE' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::TIMEVALUE',
    'argumentCount' => '1' 
    ),
    'TINV' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::TINV',
    'argumentCount' => '2' 
    ),
    'TODAY' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DATENOW',
    'argumentCount' => '0' 
    ),
    'TRANSPOSE' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::TRANSPOSE',
    'argumentCount' => '1' 
    ),
    'TREND' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::TREND',
    'argumentCount' => '1-4' 
    ),
    'TRIM' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::TRIMSPACES',
    'argumentCount' => '1' 
    ),
    'TRIMMEAN' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::TRIMMEAN',
    'argumentCount' => '2' 
    ),
    'TRUE' => array(
    'category' => Calculation\Categories::CATEGORY_LOGICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Logical::TRUE',
    'argumentCount' => '0' 
    ),
    'TRUNC' => array(
    'category' => Calculation\Categories::CATEGORY_MATH_AND_TRIG,
    'functionCall' => '\\PHPExcel\\Calculation\\MathTrig::TRUNC',
    'argumentCount' => '1,2' 
    ),
    'TTEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '4' 
    ),
    'TYPE' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::TYPE',
    'argumentCount' => '1' 
    ),
    'UPPER' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::UPPERCASE',
    'argumentCount' => '1' 
    ),
    'USDOLLAR' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '2' 
    ),
    'VALUE' => array(
    'category' => Calculation\Categories::CATEGORY_TEXT_AND_DATA,
    'functionCall' => '\\PHPExcel\\Calculation\\TextData::VALUE',
    'argumentCount' => '1' 
    ),
    'VAR' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::VARFunc',
    'argumentCount' => '1+' 
    ),
    'VARA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::VARA',
    'argumentCount' => '1+' 
    ),
    'VARP' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::VARP',
    'argumentCount' => '1+' 
    ),
    'VARPA' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::VARPA',
    'argumentCount' => '1+' 
    ),
    'VDB' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '5-7' 
    ),
    'VERSION' => array(
    'category' => Calculation\Categories::CATEGORY_INFORMATION,
    'functionCall' => 'Calculation\Categories::VERSION',
    'argumentCount' => '0' 
    ),
    'VLOOKUP' => array(
    'category' => Calculation\Categories::CATEGORY_LOOKUP_AND_REFERENCE,
    'functionCall' => '\\PHPExcel\\Calculation\\LookupRef::VLOOKUP',
    'argumentCount' => '3,4' 
    ),
    'WEEKDAY' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::DAYOFWEEK',
    'argumentCount' => '1,2' 
    ),
    'WEEKNUM' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::WEEKOFYEAR',
    'argumentCount' => '1,2' 
    ),
    'WEIBULL' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::WEIBULL',
    'argumentCount' => '4' 
    ),
    'WORKDAY' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::WORKDAY',
    'argumentCount' => '2+' 
    ),
    'XIRR' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::XIRR',
    'argumentCount' => '2,3' 
    ),
    'XNPV' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::XNPV',
    'argumentCount' => '3' 
    ),
    'YEAR' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::YEAR',
    'argumentCount' => '1' 
    ),
    'YEARFRAC' => array(
    'category' => Calculation\Categories::CATEGORY_DATE_AND_TIME,
    'functionCall' => '\\PHPExcel\\Calculation\\DateTime::YEARFRAC',
    'argumentCount' => '2,3' 
    ),
    'YIELD' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => 'Calculation\Categories::DUMMY',
    'argumentCount' => '6,7' 
    ),
    'YIELDDISC' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::YIELDDISC',
    'argumentCount' => '4,5' 
    ),
    'YIELDMAT' => array(
    'category' => Calculation\Categories::CATEGORY_FINANCIAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Financial::YIELDMAT',
    'argumentCount' => '5,6' 
    ),
    'ZTEST' => array(
    'category' => Calculation\Categories::CATEGORY_STATISTICAL,
    'functionCall' => '\\PHPExcel\\Calculation\\Statistical::ZTEST',
    'argumentCount' => '2-3' 
    ) 
    );
    
    // Internal functions used for special control purposes
    private static $controlFunctions = array(
    'MKMATRIX' => array(
    'argumentCount' => '*',
    'functionCall' => 'self::mkMatrix' 
    ) 
    );
    public function __construct(Spreadsheet $spreadsheet = null) {
        $this->delta = 1 * pow(10, 0 - ini_get('precision'));
        
        $this->spreadsheet = $spreadsheet;
        $this->cyclicReferenceStack = new CalcEngine\CyclicReferenceStack();
        $this->_debugLog = new CalcEngine\Logger($this->cyclicReferenceStack);
    }
    private static function loadLocales() {
        $localeFileDirectory = PHPEXCEL_ROOT . 'PHPExcel/locale/';
        foreach ( glob($localeFileDirectory . '/*', GLOB_ONLYDIR) as $filename ) {
            $filename = substr($filename, strlen($localeFileDirectory) + 1);
            if ($filename != 'en') {
                self::$validLocaleLanguages[] = $filename;
            }
        }
    }
    
    /**
     * Get an instance of this class
     *
     * @access public
     * @param Spreadsheet $spreadsheet
     *            Injected spreadsheet for working with a PHPExcel Spreadsheet object,
     *            or NULL to create a standalone claculation engine
     * @return Calculation
     */
    public static function getInstance(Spreadsheet $spreadsheet = null) {
        if ($spreadsheet !== null) {
            $instance = $spreadsheet->getCalculationEngine();
            if (isset($instance)) {
                return $instance;
            }
        }
        
        if (!isset(self::$instance) || (self::$instance === null)) {
            self::$instance = new \PHPExcel\Calculation();
        }
        
        return self::$instance;
    }
    
    /**
     * Unset an instance of this class
     *
     * @access public
     * @param Spreadsheet $spreadsheet
     *            Injected spreadsheet identifying the instance to unset
     */
    public function __destruct() {
        $this->workbook = null;
    }
    
    /**
     * Flush the calculation cache for any existing instance of this class
     * but only if a \PHPExcel\Calculation instance exists
     *
     * @access public
     * @return null
     */
    public function flushInstance() {
        $this->clearCalculationCache();
    }
    
    /**
     * Get the debuglog for this claculation engine instance
     *
     * @access public
     * @return CalcEngine\Logger
     */
    public function getDebugLog() {
        return $this->_debugLog;
    }
    
    /**
     * __clone implementation.
     * Cloning should not be allowed in a Singleton!
     *
     * @access public
     * @throws Calculation\Exception
     */
    final public function __clone() {
        throw new Calculation\Exception('Cloning the calculation engine is not allowed!');
    }
    
    /**
     * Return the locale-specific translation of TRUE
     *
     * @access public
     * @return string locale-specific translation of TRUE
     */
    public static function getTRUE() {
        return self::$localeBoolean['TRUE'];
    }
    
    /**
     * Return the locale-specific translation of FALSE
     *
     * @access public
     * @return string locale-specific translation of FALSE
     */
    public static function getFALSE() {
        return self::$localeBoolean['FALSE'];
    }
    
    /**
     * Set the Array Return Type (Array or Value of first element in the array)
     *
     * @access public
     * @param string $returnType
     *            Array return type
     * @return boolean Success or failure
     */
    public static function setArrayReturnType($returnType) {
        if (($returnType == self::RETURN_ARRAY_AS_VALUE) || ($returnType == self::RETURN_ARRAY_AS_ERROR) || ($returnType == self::RETURN_ARRAY_AS_ARRAY)) {
            self::$returnArrayAsType = $returnType;
            return true;
        }
        return false;
    }
    
    /**
     * Return the Array Return Type (Array or Value of first element in the array)
     *
     * @access public
     * @return string $returnType Array return type
     */
    public static function getArrayReturnType() {
        return self::$returnArrayAsType;
    }
    
    /**
     * Is calculation caching enabled?
     *
     * @access public
     * @return boolean
     */
    public function getCalculationCacheEnabled() {
        return $this->calculationCacheEnabled;
    }
    
    /**
     * Enable/disable calculation cache
     *
     * @access public
     * @param boolean $pValue            
     */
    public function setCalculationCacheEnabled($pValue = true) {
        $this->calculationCacheEnabled = $pValue;
        $this->clearCalculationCache();
    }
    
    /**
     * Enable calculation cache
     */
    public function enableCalculationCache() {
        $this->setCalculationCacheEnabled(true);
    }
    
    /**
     * Disable calculation cache
     */
    public function disableCalculationCache() {
        $this->setCalculationCacheEnabled(false);
    }
    
    /**
     * Clear calculation cache
     */
    public function clearCalculationCache() {
        $this->calculationCache = array();
    }
    
    /**
     * Clear calculation cache for a specified worksheet
     *
     * @param string $worksheetName            
     */
    public function clearCalculationCacheForWorksheet($worksheetName) {
        if (isset($this->calculationCache[$worksheetName])) {
            unset($this->calculationCache[$worksheetName]);
        }
    }
    
    /**
     * Rename calculation cache for a specified worksheet
     *
     * @param string $fromWorksheetName            
     * @param string $toWorksheetName            
     */
    public function renameCalculationCacheForWorksheet($fromWorksheetName, $toWorksheetName) {
        if (isset($this->calculationCache[$fromWorksheetName])) {
            $this->calculationCache[$toWorksheetName] = &$this->calculationCache[$fromWorksheetName];
            unset($this->calculationCache[$fromWorksheetName]);
        }
    }
    
    /**
     * Get the currently defined locale code
     *
     * @return string
     */
    public function getLocale() {
        return self::$localeLanguage;
    }
    
    /**
     * Set the locale code
     *
     * @param string $locale
     *            The locale to use for formula translation
     * @return boolean
     */
    public function setLocale($locale = 'en_us') {
        // Identify our locale and language
        $language = $locale = strtolower($locale);
        if (strpos($locale, '_') !== false) {
            list($language) = explode('_', $locale);
        }
        
        if (count(self::$validLocaleLanguages) == 1) {
            self::loadLocales();
        }
        // Test whether we have any language data for this language (any locale)
        if (in_array($language, self::$validLocaleLanguages)) {
            // initialise language/locale settings
            self::$localeFunctions = array();
            self::$localeArgumentSeparator = ',';
            self::$localeBoolean = array(
            'TRUE' => 'TRUE',
            'FALSE' => 'FALSE',
            'NULL' => 'NULL' 
            );
            // Default is English, if user isn't requesting english, then read the necessary data from the locale files
            if ($locale != 'en_us') {
                // Search for a file with a list of function names for locale
                $functionNamesFile = PHPEXCEL_ROOT . 'PHPExcel' . DIRECTORY_SEPARATOR . 'locale' . DIRECTORY_SEPARATOR . str_replace('_', DIRECTORY_SEPARATOR, $locale) . DIRECTORY_SEPARATOR . 'functions';
                if (!file_exists($functionNamesFile)) {
                    // If there isn't a locale specific function file, look for a language specific function file
                    $functionNamesFile = PHPEXCEL_ROOT . 'PHPExcel' . DIRECTORY_SEPARATOR . 'locale' . DIRECTORY_SEPARATOR . $language . DIRECTORY_SEPARATOR . 'functions';
                    if (!file_exists($functionNamesFile)) {
                        return false;
                    }
                }
                // Retrieve the list of locale or language specific function names
                $localeFunctions = file($functionNamesFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
                foreach ( $localeFunctions as $localeFunction ) {
                    list($localeFunction) = explode('##', $localeFunction); // Strip out comments
                    if (strpos($localeFunction, '=') !== false) {
                        list($fName, $lfName) = explode('=', $localeFunction);
                        $fName = trim($fName);
                        $lfName = trim($lfName);
                        if ((isset(self::$PHPExcelFunctions[$fName])) && ($lfName != '') && ($fName != $lfName)) {
                            self::$localeFunctions[$fName] = $lfName;
                        }
                    }
                }
                // Default the TRUE and FALSE constants to the locale names of the TRUE() and FALSE() functions
                if (isset(self::$localeFunctions['TRUE'])) {
                    self::$localeBoolean['TRUE'] = self::$localeFunctions['TRUE'];
                }
                if (isset(self::$localeFunctions['FALSE'])) {
                    self::$localeBoolean['FALSE'] = self::$localeFunctions['FALSE'];
                }
                
                $configFile = PHPEXCEL_ROOT . 'PHPExcel' . DIRECTORY_SEPARATOR . 'locale' . DIRECTORY_SEPARATOR . str_replace('_', DIRECTORY_SEPARATOR, $locale) . DIRECTORY_SEPARATOR . 'config';
                if (!file_exists($configFile)) {
                    $configFile = PHPEXCEL_ROOT . 'PHPExcel' . DIRECTORY_SEPARATOR . 'locale' . DIRECTORY_SEPARATOR . $language . DIRECTORY_SEPARATOR . 'config';
                }
                if (file_exists($configFile)) {
                    $localeSettings = file($configFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
                    foreach ( $localeSettings as $localeSetting ) {
                        list($localeSetting) = explode('##', $localeSetting); // Strip out comments
                        if (strpos($localeSetting, '=') !== false) {
                            list($settingName, $settingValue) = explode('=', $localeSetting);
                            $settingName = strtoupper(trim($settingName));
                            switch ($settingName) {
                                case 'ARGUMENTSEPARATOR' :
                                    self::$localeArgumentSeparator = trim($settingValue);
                                    break;
                            }
                        }
                    }
                }
            }
            
            self::$functionReplaceFromExcel = self::$functionReplaceToExcel = self::$functionReplaceFromLocale = self::$functionReplaceToLocale = null;
            self::$localeLanguage = $locale;
            return true;
        }
        return false;
    }
    public static function translateSeparator($fromSeparator, $toSeparator, $formula, &$inBraces) {
        $strlen = mb_strlen($formula);
        for($i = 0; $i < $strlen; ++$i) {
            $chr = mb_substr($formula, $i, 1);
            switch ($chr) {
                case '{' :
                    $inBraces = true;
                    break;
                case '}' :
                    $inBraces = false;
                    break;
                case $fromSeparator :
                    if (!$inBraces) {
                        $formula = mb_substr($formula, 0, $i) . $toSeparator . mb_substr($formula, $i + 1);
                    }
            }
        }
        return $formula;
    }
    private static function translateFormula($from, $to, $formula, $fromSeparator, $toSeparator) {
        // Convert any Excel function names to the required language
        if (self::$localeLanguage !== 'en_us') {
            $inBraces = false;
            // If there is the possibility of braces within a quoted string, then we don't treat those as matrix indicators
            if (strpos($formula, '"') !== false) {
                // So instead we skip replacing in any quoted strings by only replacing in every other array element after we've exploded
                // the formula
                $temp = explode('"', $formula);
                $i = false;
                foreach ( $temp as &$value ) {
                    // Only count/replace in alternating array entries
                    if ($i = !$i) {
                        $value = preg_replace($from, $to, $value);
                        $value = self::translateSeparator($fromSeparator, $toSeparator, $value, $inBraces);
                    }
                }
                unset($value);
                // Then rebuild the formula string
                $formula = implode('"', $temp);
            } else {
                // If there's no quoted strings, then we do a simple count/replace
                $formula = preg_replace($from, $to, $formula);
                $formula = self::translateSeparator($fromSeparator, $toSeparator, $formula, $inBraces);
            }
        }
        
        return $formula;
    }
    private static $functionReplaceFromExcel = null;
    private static $functionReplaceToLocale = null;
    public function _translateFormulaToLocale($formula) {
        if (self::$functionReplaceFromExcel === null) {
            self::$functionReplaceFromExcel = array();
            foreach ( array_keys(self::$localeFunctions) as $excelFunctionName ) {
                self::$functionReplaceFromExcel[] = '/(@?[^\w\.])' . preg_quote($excelFunctionName) . '([\s]*\()/Ui';
            }
            foreach ( array_keys(self::$localeBoolean) as $excelBoolean ) {
                self::$functionReplaceFromExcel[] = '/(@?[^\w\.])' . preg_quote($excelBoolean) . '([^\w\.])/Ui';
            }
        }
        
        if (self::$functionReplaceToLocale === null) {
            self::$functionReplaceToLocale = array();
            foreach ( array_values(self::$localeFunctions) as $localeFunctionName ) {
                self::$functionReplaceToLocale[] = '$1' . trim($localeFunctionName) . '$2';
            }
            foreach ( array_values(self::$localeBoolean) as $localeBoolean ) {
                self::$functionReplaceToLocale[] = '$1' . trim($localeBoolean) . '$2';
            }
        }
        
        return self::translateFormula(self::$functionReplaceFromExcel, self::$functionReplaceToLocale, $formula, ',', self::$localeArgumentSeparator);
    }
    private static $functionReplaceFromLocale = null;
    private static $functionReplaceToExcel = null;
    public function _translateFormulaToEnglish($formula) {
        if (self::$functionReplaceFromLocale === null) {
            self::$functionReplaceFromLocale = array();
            foreach ( array_values(self::$localeFunctions) as $localeFunctionName ) {
                self::$functionReplaceFromLocale[] = '/(@?[^\w\.])' . preg_quote($localeFunctionName) . '([\s]*\()/Ui';
            }
            foreach ( array_values(self::$localeBoolean) as $excelBoolean ) {
                self::$functionReplaceFromLocale[] = '/(@?[^\w\.])' . preg_quote($excelBoolean) . '([^\w\.])/Ui';
            }
        }
        
        if (self::$functionReplaceToExcel === null) {
            self::$functionReplaceToExcel = array();
            foreach ( array_keys(self::$localeFunctions) as $excelFunctionName ) {
                self::$functionReplaceToExcel[] = '$1' . trim($excelFunctionName) . '$2';
            }
            foreach ( array_keys(self::$localeBoolean) as $excelBoolean ) {
                self::$functionReplaceToExcel[] = '$1' . trim($excelBoolean) . '$2';
            }
        }
        
        return self::translateFormula(self::$functionReplaceFromLocale, self::$functionReplaceToExcel, $formula, self::$localeArgumentSeparator, ',');
    }
    public static function localeFunc($function) {
        if (self::$localeLanguage !== 'en_us') {
            $functionName = trim($function, '(');
            if (isset(self::$localeFunctions[$functionName])) {
                $brace = ($functionName != $function);
                $function = self::$localeFunctions[$functionName];
                if ($brace) {
                    $function .= '(';
                }
            }
        }
        return $function;
    }
    
    /**
     * Wrap string values in quotes
     *
     * @param mixed $value            
     * @return mixed
     */
    public static function wrapResult($value) {
        if (is_string($value)) {
            // Error values cannot be "wrapped"
            if (preg_match('/^' . self::CALCULATION_REGEXP_ERROR . '$/i', $value, $match)) {
                // Return Excel errors "as is"
                return $value;
            }
            // Return strings wrapped in quotes
            return '"' . $value . '"';
            // Convert numeric errors to NaN error
        } elseif ((is_float($value)) && ((is_nan($value)) || (is_infinite($value)))) {
            return Calculation\Functions::NAN();
        }
        
        return $value;
    }
    
    /**
     * Remove quotes used as a wrapper to identify string values
     *
     * @param mixed $value            
     * @return mixed
     */
    public static function unwrapResult($value) {
        if (is_string($value)) {
            if ((isset($value{0})) && ($value{0} == '"') && (substr($value, -1) == '"')) {
                return substr($value, 1, -1);
            }
            // Convert numeric errors to NAN error
        } elseif ((is_float($value)) && ((is_nan($value)) || (is_infinite($value)))) {
            return Calculation\Functions::NAN();
        }
        return $value;
    }
    
    /**
     * Calculate cell value (using formula from a cell ID)
     * Retained for backward compatibility
     *
     * @access public
     * @param Cell $pCell
     *            Cell to calculate
     * @return mixed
     * @throws Calculation\Exception
     */
    public function calculate(Cell $pCell = null) {
        try {
            return $this->calculateCellValue($pCell);
        } catch ( Exception $e ) {
            throw new Calculation\Exception($e->getMessage());
        }
    }
    
    /**
     * Calculate the value of a cell formula
     *
     * @access public
     * @param Cell $pCell
     *            Cell to calculate
     * @param Boolean $resetLog
     *            Flag indicating whether the debug log should be reset or not
     * @return mixed
     * @throws Calculation\Exception
     */
    public function calculateCellValue(Cell $pCell = null, $resetLog = true) {
        if ($pCell === null) {
            return null;
        }
        
        $returnArrayAsType = self::$returnArrayAsType;
        if ($resetLog) {
            // Initialise the logging settings if requested
            $this->formulaError = null;
            $this->_debugLog->clearLog();
            $this->cyclicReferenceStack->clear();
            $this->cyclicFormulaCounter = 1;
            
            self::$returnArrayAsType = self::RETURN_ARRAY_AS_ARRAY;
        }
        
        // Execute the calculation for the cell formula
        $this->cellStack[] = array(
        'sheet' => $pCell->getWorksheet()->getTitle(),
        'cell' => $pCell->getCoordinate() 
        );
        try {
            $result = self::unwrapResult($this->_calculateFormulaValue($pCell->getValue(), $pCell->getCoordinate(), $pCell));
            $cellAddress = array_pop($this->cellStack);
            $this->spreadsheet->getSheetByName($cellAddress['sheet'])->getCell($cellAddress['cell']);
        } catch ( Exception $e ) {
            $cellAddress = array_pop($this->cellStack);
            $this->spreadsheet->getSheetByName($cellAddress['sheet'])->getCell($cellAddress['cell']);
            throw new Calculation\Exception($e->getMessage());
        }
        
        if ((is_array($result)) && (self::$returnArrayAsType != self::RETURN_ARRAY_AS_ARRAY)) {
            self::$returnArrayAsType = $returnArrayAsType;
            $testResult = Calculation\Functions::flattenArray($result);
            if (self::$returnArrayAsType == self::RETURN_ARRAY_AS_ERROR) {
                return Calculation\Functions::VALUE();
            }
            // If there's only a single cell in the array, then we allow it
            if (count($testResult) != 1) {
                // If keys are numeric, then it's a matrix result rather than a cell range result, so we permit it
                $r = array_keys($result);
                $r = array_shift($r);
                if (!is_numeric($r)) {
                    return Calculation\Functions::VALUE();
                }
                if (is_array($result[$r])) {
                    $c = array_keys($result[$r]);
                    $c = array_shift($c);
                    if (!is_numeric($c)) {
                        return Calculation\Functions::VALUE();
                    }
                }
            }
            $result = array_shift($testResult);
        }
        self::$returnArrayAsType = $returnArrayAsType;
        
        if ($result === null) {
            return 0;
        } elseif ((is_float($result)) && ((is_nan($result)) || (is_infinite($result)))) {
            return Calculation\Functions::NAN();
        }
        return $result;
    }
    
    /**
     * Validate and parse a formula string
     *
     * @param string $formula
     *            Formula to parse
     * @return array
     * @throws Calculation\Exception
     */
    public function parseFormula($formula) {
        // Basic validation that this is indeed a formula
        // We return an empty array if not
        $formula = trim($formula);
        if ((!isset($formula{0})) || ($formula{0} != '=')) {
            return array();
        }
        $formula = ltrim(substr($formula, 1));
        if (!isset($formula{0})) {
            return array();
        }
        
        // Parse the formula and return the token stack
        return $this->_parseFormula($formula);
    }
    
    /**
     * Calculate the value of a formula
     *
     * @param string $formula
     *            Formula to parse
     * @param string $cellID
     *            Address of the cell to calculate
     * @param Cell $pCell
     *            Cell to calculate
     * @return mixed
     * @throws Calculation\Exception
     */
    public function calculateFormula($formula, $cellID = null, Cell $pCell = null) {
        // Initialise the logging settings
        $this->formulaError = null;
        $this->_debugLog->clearLog();
        $this->cyclicReferenceStack->clear();
        
        if ($this->spreadsheet !== null && $cellID === null && $pCell === null) {
            $cellID = 'A1';
            $pCell = $this->spreadsheet->getActiveSheet()->getCell($cellID);
        } else {
            // Disable calculation cacheing because it only applies to cell calculations, not straight formulae
            // But don't actually flush any cache
            $resetCache = $this->getCalculationCacheEnabled();
            $this->calculationCacheEnabled = false;
        }
        
        // Execute the calculation
        try {
            $result = self::unwrapResult($this->_calculateFormulaValue($formula, $cellID, $pCell));
        } catch ( Exception $e ) {
            throw new Calculation\Exception($e->getMessage());
        }
        
        if ($this->spreadsheet === null) {
            // Reset calculation cacheing to its previous state
            $this->calculationCacheEnabled = $resetCache;
        }
        
        return $result;
    }
    public function getValueFromCache($cellReference, &$cellValue) {
        // Is calculation cacheing enabled?
        // Is the value present in calculation cache?
        $this->_debugLog->writeDebugLog('Testing cache value for cell ', $cellReference);
        if (($this->calculationCacheEnabled) && (isset($this->calculationCache[$cellReference]))) {
            $this->_debugLog->writeDebugLog('Retrieving value for cell ', $cellReference, ' from cache');
            // Return the cached result
            $cellValue = $this->calculationCache[$cellReference];
            return true;
        }
        return false;
    }
    public function saveValueToCache($cellReference, $cellValue) {
        if ($this->calculationCacheEnabled) {
            $this->calculationCache[$cellReference] = $cellValue;
        }
    }
    
    /**
     * Parse a cell formula and calculate its value
     *
     * @param string $formula
     *            The formula to parse and calculate
     * @param string $cellID
     *            The ID (e.g. A3) of the cell that we are calculating
     * @param Cell $pCell
     *            Cell to calculate
     * @return mixed
     * @throws Calculation\Exception
     */
    public function _calculateFormulaValue($formula, $cellID = null, Cell $pCell = null) {
        $cellValue = null;
        
        // Basic validation that this is indeed a formula
        // We simply return the cell value if not
        $formula = trim($formula);
        if ($formula{0} != '=') {
            return self::wrapResult($formula);
        }
        $formula = ltrim(substr($formula, 1));
        if (!isset($formula{0})) {
            return self::wrapResult($formula);
        }
        
        $pCellParent = ($pCell !== null) ? $pCell->getWorksheet() : null;
        $wsTitle = ($pCellParent !== null) ? $pCellParent->getTitle() : "\x00Wrk";
        $wsCellReference = $wsTitle . '!' . $cellID;
        
        if (($cellID !== null) && ($this->getValueFromCache($wsCellReference, $cellValue))) {
            return $cellValue;
        }
        
        if (($wsTitle{0} !== "\x00") && ($this->cyclicReferenceStack->onStack($wsCellReference))) {
            if ($this->cyclicFormulaCount <= 0) {
                $this->cyclicFormulaCell = '';
                return $this->raiseFormulaError('Cyclic Reference in Formula');
            } elseif ($this->cyclicFormulaCell === $wsCellReference) {
                ++$this->cyclicFormulaCounter;
                if ($this->cyclicFormulaCounter >= $this->cyclicFormulaCount) {
                    $this->cyclicFormulaCell = '';
                    return $cellValue;
                }
            } elseif ($this->cyclicFormulaCell == '') {
                if ($this->cyclicFormulaCounter >= $this->cyclicFormulaCount) {
                    return $cellValue;
                }
                $this->cyclicFormulaCell = $wsCellReference;
            }
        }
        
        // Parse the formula onto the token stack and calculate the value
        $this->cyclicReferenceStack->push($wsCellReference);
        $cellValue = $this->processTokenStack($this->_parseFormula($formula, $pCell), $cellID, $pCell);
        $this->cyclicReferenceStack->pop();
        
        // Save to calculation cache
        if ($cellID !== null) {
            $this->saveValueToCache($wsCellReference, $cellValue);
        }
        
        // Return the calculated value
        return $cellValue;
    }
    
    /**
     * Ensure that paired matrix operands are both matrices and of the same size
     *
     * @param
     *            mixed &$operand1 First matrix operand
     * @param
     *            mixed &$operand2 Second matrix operand
     * @param integer $resize
     *            Flag indicating whether the matrices should be resized to match
     *            and (if so), whether the smaller dimension should grow or the
     *            larger should shrink.
     *            0 = no resize
     *            1 = shrink to fit
     *            2 = extend to fit
     */
    private static function checkMatrixOperands(&$operand1, &$operand2, $resize = 1) {
        // Examine each of the two operands, and turn them into an array if they aren't one already
        // Note that this function should only be called if one or both of the operand is already an array
        if (!is_array($operand1)) {
            list($matrixRows, $matrixColumns) = self::getMatrixDimensions($operand2);
            $operand1 = array_fill(0, $matrixRows, array_fill(0, $matrixColumns, $operand1));
            $resize = 0;
        } elseif (!is_array($operand2)) {
            list($matrixRows, $matrixColumns) = self::getMatrixDimensions($operand1);
            $operand2 = array_fill(0, $matrixRows, array_fill(0, $matrixColumns, $operand2));
            $resize = 0;
        }
        
        list($matrix1Rows, $matrix1Columns) = self::getMatrixDimensions($operand1);
        list($matrix2Rows, $matrix2Columns) = self::getMatrixDimensions($operand2);
        if (($matrix1Rows == $matrix2Columns) && ($matrix2Rows == $matrix1Columns)) {
            $resize = 1;
        }
        
        if ($resize == 2) {
            // Given two matrices of (potentially) unequal size, convert the smaller in each dimension to match the larger
            self::resizeMatricesExtend($operand1, $operand2, $matrix1Rows, $matrix1Columns, $matrix2Rows, $matrix2Columns);
        } elseif ($resize == 1) {
            // Given two matrices of (potentially) unequal size, convert the larger in each dimension to match the smaller
            self::resizeMatricesShrink($operand1, $operand2, $matrix1Rows, $matrix1Columns, $matrix2Rows, $matrix2Columns);
        }
        return array(
        $matrix1Rows,
        $matrix1Columns,
        $matrix2Rows,
        $matrix2Columns 
        );
    }
    
    /**
     * Read the dimensions of a matrix, and re-index it with straight numeric keys starting from row 0, column 0
     *
     * @param
     *            mixed &$matrix matrix operand
     * @return array An array comprising the number of rows, and number of columns
     */
    private static function getMatrixDimensions(&$matrix) {
        $matrixRows = count($matrix);
        $matrixColumns = 0;
        foreach ( $matrix as $rowKey => $rowValue ) {
            $matrixColumns = max(count($rowValue), $matrixColumns);
            if (!is_array($rowValue)) {
                $matrix[$rowKey] = array(
                $rowValue 
                );
            } else {
                $matrix[$rowKey] = array_values($rowValue);
            }
        }
        $matrix = array_values($matrix);
        return array(
        $matrixRows,
        $matrixColumns 
        );
    }
    
    /**
     * Ensure that paired matrix operands are both matrices of the same size
     *
     * @param
     *            mixed &$matrix1 First matrix operand
     * @param
     *            mixed &$matrix2 Second matrix operand
     * @param integer $matrix1Rows
     *            Row size of first matrix operand
     * @param integer $matrix1Columns
     *            Column size of first matrix operand
     * @param integer $matrix2Rows
     *            Row size of second matrix operand
     * @param integer $matrix2Columns
     *            Column size of second matrix operand
     */
    private static function resizeMatricesShrink(&$matrix1, &$matrix2, $matrix1Rows, $matrix1Columns, $matrix2Rows, $matrix2Columns) {
        if (($matrix2Columns < $matrix1Columns) || ($matrix2Rows < $matrix1Rows)) {
            if ($matrix2Rows < $matrix1Rows) {
                for($i = $matrix2Rows; $i < $matrix1Rows; ++$i) {
                    unset($matrix1[$i]);
                }
            }
            if ($matrix2Columns < $matrix1Columns) {
                for($i = 0; $i < $matrix1Rows; ++$i) {
                    for($j = $matrix2Columns; $j < $matrix1Columns; ++$j) {
                        unset($matrix1[$i][$j]);
                    }
                }
            }
        }
        
        if (($matrix1Columns < $matrix2Columns) || ($matrix1Rows < $matrix2Rows)) {
            if ($matrix1Rows < $matrix2Rows) {
                for($i = $matrix1Rows; $i < $matrix2Rows; ++$i) {
                    unset($matrix2[$i]);
                }
            }
            if ($matrix1Columns < $matrix2Columns) {
                for($i = 0; $i < $matrix2Rows; ++$i) {
                    for($j = $matrix1Columns; $j < $matrix2Columns; ++$j) {
                        unset($matrix2[$i][$j]);
                    }
                }
            }
        }
    }
    
    /**
     * Ensure that paired matrix operands are both matrices of the same size
     *
     * @param
     *            mixed &$matrix1 First matrix operand
     * @param
     *            mixed &$matrix2 Second matrix operand
     * @param integer $matrix1Rows
     *            Row size of first matrix operand
     * @param integer $matrix1Columns
     *            Column size of first matrix operand
     * @param integer $matrix2Rows
     *            Row size of second matrix operand
     * @param integer $matrix2Columns
     *            Column size of second matrix operand
     */
    private static function resizeMatricesExtend(&$matrix1, &$matrix2, $matrix1Rows, $matrix1Columns, $matrix2Rows, $matrix2Columns) {
        if (($matrix2Columns < $matrix1Columns) || ($matrix2Rows < $matrix1Rows)) {
            if ($matrix2Columns < $matrix1Columns) {
                for($i = 0; $i < $matrix2Rows; ++$i) {
                    $x = $matrix2[$i][$matrix2Columns - 1];
                    for($j = $matrix2Columns; $j < $matrix1Columns; ++$j) {
                        $matrix2[$i][$j] = $x;
                    }
                }
            }
            if ($matrix2Rows < $matrix1Rows) {
                $x = $matrix2[$matrix2Rows - 1];
                for($i = 0; $i < $matrix1Rows; ++$i) {
                    $matrix2[$i] = $x;
                }
            }
        }
        
        if (($matrix1Columns < $matrix2Columns) || ($matrix1Rows < $matrix2Rows)) {
            if ($matrix1Columns < $matrix2Columns) {
                for($i = 0; $i < $matrix1Rows; ++$i) {
                    $x = $matrix1[$i][$matrix1Columns - 1];
                    for($j = $matrix1Columns; $j < $matrix2Columns; ++$j) {
                        $matrix1[$i][$j] = $x;
                    }
                }
            }
            if ($matrix1Rows < $matrix2Rows) {
                $x = $matrix1[$matrix1Rows - 1];
                for($i = 0; $i < $matrix2Rows; ++$i) {
                    $matrix1[$i] = $x;
                }
            }
        }
    }
    
    /**
     * Format details of an operand for display in the log (based on operand type)
     *
     * @param mixed $value
     *            First matrix operand
     * @return mixed
     */
    private function showValue($value) {
        if ($this->_debugLog->getWriteDebugLog()) {
            $testArray = Calculation\Functions::flattenArray($value);
            if (count($testArray) == 1) {
                $value = array_pop($testArray);
            }
            
            if (is_array($value)) {
                $returnMatrix = array();
                $pad = $rpad = ', ';
                foreach ( $value as $row ) {
                    if (is_array($row)) {
                        $returnMatrix[] = implode($pad, array_map(array(
                        $this,
                        'showValue' 
                        ), $row));
                        $rpad = '; ';
                    } else {
                        $returnMatrix[] = $this->showValue($row);
                    }
                }
                return '{ ' . implode($rpad, $returnMatrix) . ' }';
            } elseif (is_string($value) && (trim($value, '"') == $value)) {
                return '"' . $value . '"';
            } elseif (is_bool($value)) {
                return ($value) ? self::$localeBoolean['TRUE'] : self::$localeBoolean['FALSE'];
            }
        }
        return Calculation\Functions::flattenSingleValue($value);
    }
    
    /**
     * Format type and details of an operand for display in the log (based on operand type)
     *
     * @param mixed $value
     *            First matrix operand
     * @return mixed
     */
    private function showTypeDetails($value) {
        if ($this->_debugLog->getWriteDebugLog()) {
            $testArray = Calculation\Functions::flattenArray($value);
            if (count($testArray) == 1) {
                $value = array_pop($testArray);
            }
            
            if ($value === null) {
                return 'a NULL value';
            } elseif (is_float($value)) {
                $typeString = 'a floating point number';
            } elseif (is_int($value)) {
                $typeString = 'an integer number';
            } elseif (is_bool($value)) {
                $typeString = 'a boolean';
            } elseif (is_array($value)) {
                $typeString = 'a matrix';
            } else {
                if ($value == '') {
                    return 'an empty string';
                } elseif ($value{0} == '#') {
                    return 'a ' . $value . ' error';
                } else {
                    $typeString = 'a string';
                }
            }
            return $typeString . ' with a value of ' . $this->showValue($value);
        }
    }
    private function convertMatrixReferences($formula) {
        static $matrixReplaceFrom = array(
        '{',
        ';',
        '}' 
        );
        static $matrixReplaceTo = array(
        'MKMATRIX(MKMATRIX(',
        '),MKMATRIX(',
        '))' 
        );
        
        // Convert any Excel matrix references to the MKMATRIX() function
        if (strpos($formula, '{') !== false) {
            // If there is the possibility of braces within a quoted string, then we don't treat those as matrix indicators
            if (strpos($formula, '"') !== false) {
                // So instead we skip replacing in any quoted strings by only replacing in every other array element after we've exploded
                // the formula
                $temp = explode('"', $formula);
                // Open and Closed counts used for trapping mismatched braces in the formula
                $openCount = $closeCount = 0;
                $i = false;
                foreach ( $temp as &$value ) {
                    // Only count/replace in alternating array entries
                    if ($i = !$i) {
                        $openCount += substr_count($value, '{');
                        $closeCount += substr_count($value, '}');
                        $value = str_replace($matrixReplaceFrom, $matrixReplaceTo, $value);
                    }
                }
                unset($value);
                // Then rebuild the formula string
                $formula = implode('"', $temp);
            } else {
                // If there's no quoted strings, then we do a simple count/replace
                $openCount = substr_count($formula, '{');
                $closeCount = substr_count($formula, '}');
                $formula = str_replace($matrixReplaceFrom, $matrixReplaceTo, $formula);
            }
            // Trap for mismatched braces and trigger an appropriate error
            if ($openCount < $closeCount) {
                if ($openCount > 0) {
                    return $this->raiseFormulaError("Formula Error: Mismatched matrix braces '}'");
                } else {
                    return $this->raiseFormulaError("Formula Error: Unexpected '}' encountered");
                }
            } elseif ($openCount > $closeCount) {
                if ($closeCount > 0) {
                    return $this->raiseFormulaError("Formula Error: Mismatched matrix braces '{'");
                } else {
                    return $this->raiseFormulaError("Formula Error: Unexpected '{' encountered");
                }
            }
        }
        
        return $formula;
    }
    private static function mkMatrix() {
        return func_get_args();
    }
    
    // Binary Operators
    // These operators always work on two values
    // Array key is the operator, the value indicates whether this is a left or right associative operator
    private static $operatorAssociativity = array(
    '^' => 0, // Exponentiation
    '*' => 0,
    '/' => 0, // Multiplication and Division
    '+' => 0,
    '-' => 0, // Addition and Subtraction
    '&' => 0, // Concatenation
    '|' => 0,
    ':' => 0, // Intersect and Range
    '>' => 0,
    '<' => 0,
    '=' => 0,
    '>=' => 0,
    '<=' => 0,
    '<>' => 0 
    ); // Comparison

    
    // Comparison (Boolean) Operators
    // These operators work on two values, but always return a boolean result
    private static $comparisonOperators = array(
    '>' => true,
    '<' => true,
    '=' => true,
    '>=' => true,
    '<=' => true,
    '<>' => true 
    );
    
    // Operator Precedence
    // This list includes all valid operators, whether binary (including boolean) or unary (such as %)
    // Array key is the operator, the value is its precedence
    private static $operatorPrecedence = array(
    ':' => 8, // Range
    '|' => 7, // Intersect
    '~' => 6, // Negation
    '%' => 5, // Percentage
    '^' => 4, // Exponentiation
    '*' => 3,
    '/' => 3, // Multiplication and Division
    '+' => 2,
    '-' => 2, // Addition and Subtraction
    '&' => 1, // Concatenation
    '>' => 0,
    '<' => 0,
    '=' => 0,
    '>=' => 0,
    '<=' => 0,
    '<>' => 0 
    ); // Comparison

    
    // Convert infix to postfix notation
    private function _parseFormula($formula, Cell $pCell = null) {
        if (($formula = $this->convertMatrixReferences(trim($formula))) === false) {
            return false;
        }
        
        // If we're using cell caching, then $pCell may well be flushed back to the cache (which detaches the parent worksheet),
        // so we store the parent worksheet so that we can re-attach it when necessary
        $pCellParent = ($pCell !== null) ? $pCell->getWorksheet() : null;
        
        $regexpMatchString = '/^(' . self::CALCULATION_REGEXP_FUNCTION . '|' . self::CALCULATION_REGEXP_CELLREF . '|' . self::CALCULATION_REGEXP_NUMBER . '|' . self::CALCULATION_REGEXP_STRING . '|' . self::CALCULATION_REGEXP_OPENBRACE . '|' . self::CALCULATION_REGEXP_NAMEDRANGE . '|' . self::CALCULATION_REGEXP_ERROR . ')/si';
        
        // Start with initialisation
        $index = 0;
        $stack = new Calculation\Token\Stack();
        $output = array();
        $expectingOperator = false; // We use this test in syntax-checking the expression to determine when a
        // - is a negation or + is a positive operator rather than an operation
        $expectingOperand = false; // We use this test in syntax-checking the expression to determine whether an operand
        // should be null in a function call
        // The guts of the lexical parser
        // Loop through the formula extracting each operator and operand in turn
        while ( true ) {
            // echo 'Assessing Expression '.substr($formula, $index), PHP_EOL;
            $opCharacter = $formula{$index}; // Get the first character of the value at the current index position
            // echo 'Initial character of expression block is '.$opCharacter, PHP_EOL;
            if ((isset(self::$comparisonOperators[$opCharacter])) && (strlen($formula) > $index) && (isset(self::$comparisonOperators[$formula{$index + 1}]))) {
                $opCharacter .= $formula{++$index};
                // echo 'Initial character of expression block is comparison operator '.$opCharacter.PHP_EOL;
            }
            
            // Find out if we're currently at the beginning of a number, variable, cell reference, function, parenthesis or operand
            $isOperandOrFunction = preg_match($regexpMatchString, substr($formula, $index), $match);
            // echo '$isOperandOrFunction is '.(($isOperandOrFunction) ? 'True' : 'False').PHP_EOL;
            // var_dump($match);
            

            if ($opCharacter == '-' && !$expectingOperator) { // Is it a negation instead of a minus?
                // echo 'Element is a Negation operator', PHP_EOL;
                $stack->push('Unary Operator', '~'); // Put a negation on the stack
                ++$index; // and drop the negation symbol
            } elseif ($opCharacter == '%' && $expectingOperator) {
                // echo 'Element is a Percentage operator', PHP_EOL;
                $stack->push('Unary Operator', '%'); // Put a percentage on the stack
                ++$index;
            } elseif ($opCharacter == '+' && !$expectingOperator) { // Positive (unary plus rather than binary operator plus) can be discarded?
                // echo 'Element is a Positive number, not Plus operator', PHP_EOL;
                ++$index; // Drop the redundant plus symbol
            } elseif ((($opCharacter == '~') || ($opCharacter == '|')) && (!$isOperandOrFunction)) { // We have to explicitly deny a tilde or pipe, because they are legal
                return $this->raiseFormulaError("Formula Error: Illegal character '~'"); // on the stack but not in the input expression
            } elseif ((isset(self::$operators[$opCharacter]) or $isOperandOrFunction) && $expectingOperator) { // Are we putting an operator on the stack?
                // echo 'Element with value '.$opCharacter.' is an Operator', PHP_EOL;
                while ( $stack->count() > 0 && ($o2 = $stack->last()) && isset(self::$operators[$o2['value']]) && @(self::$operatorAssociativity[$opCharacter] ? self::$operatorPrecedence[$opCharacter] < self::$operatorPrecedence[$o2['value']] : self::$operatorPrecedence[$opCharacter] <= self::$operatorPrecedence[$o2['value']]) ) {
                    $output[] = $stack->pop(); // Swap operands and higher precedence operators from the stack to the output
                }
                $stack->push('Binary Operator', $opCharacter); // Finally put our current operator onto the stack
                ++$index;
                $expectingOperator = false;
            } elseif ($opCharacter == ')' && $expectingOperator) { // Are we expecting to close a parenthesis?
                // echo 'Element is a Closing bracket', PHP_EOL;
                $expectingOperand = false;
                while ( ($o2 = $stack->pop()) && $o2['value'] != '(' ) { // Pop off the stack back to the last (
                    if ($o2 === null) {
                        return $this->raiseFormulaError('Formula Error: Unexpected closing brace ")"');
                    } else {
                        $output[] = $o2;
                    }
                }
                $d = $stack->last(2);
                if (preg_match('/^' . self::CALCULATION_REGEXP_FUNCTION . '$/i', $d['value'], $matches)) { // Did this parenthesis just close a function?
                    $functionName = $matches[1]; // Get the function name
                    // echo 'Closed Function is '.$functionName, PHP_EOL;
                    $d = $stack->pop();
                    $argumentCount = $d['value']; // See how many arguments there were (argument count is the next value stored on the stack)
                    // if ($argumentCount == 0) {
                    // echo 'With no arguments', PHP_EOL;
                    // } elseif ($argumentCount == 1) {
                    // echo 'With 1 argument', PHP_EOL;
                    // } else {
                    // echo 'With '.$argumentCount.' arguments', PHP_EOL;
                    // }
                    $output[] = $d; // Dump the argument count on the output
                    $output[] = $stack->pop(); // Pop the function and push onto the output
                    if (isset(self::$controlFunctions[$functionName])) {
                        // echo 'Built-in function '.$functionName, PHP_EOL;
                        $expectedArgumentCount = self::$controlFunctions[$functionName]['argumentCount'];
                        $functionCall = self::$controlFunctions[$functionName]['functionCall'];
                    } elseif (isset(self::$PHPExcelFunctions[$functionName])) {
                        // echo 'PHPExcel function '.$functionName, PHP_EOL;
                        $expectedArgumentCount = self::$PHPExcelFunctions[$functionName]['argumentCount'];
                        $functionCall = self::$PHPExcelFunctions[$functionName]['functionCall'];
                    } else { // did we somehow push a non-function on the stack? this should never happen
                        return $this->raiseFormulaError("Formula Error: Internal error, non-function on stack");
                    }
                    // Check the argument count
                    $argumentCountError = false;
                    if (is_numeric($expectedArgumentCount)) {
                        if ($expectedArgumentCount < 0) {
                            // echo '$expectedArgumentCount is between 0 and '.abs($expectedArgumentCount), PHP_EOL;
                            if ($argumentCount > abs($expectedArgumentCount)) {
                                $argumentCountError = true;
                                $expectedArgumentCountString = 'no more than ' . abs($expectedArgumentCount);
                            }
                        } else {
                            // echo '$expectedArgumentCount is numeric '.$expectedArgumentCount, PHP_EOL;
                            if ($argumentCount != $expectedArgumentCount) {
                                $argumentCountError = true;
                                $expectedArgumentCountString = $expectedArgumentCount;
                            }
                        }
                    } elseif ($expectedArgumentCount != '*') {
                        $isOperandOrFunction = preg_match('/(\d*)([-+,])(\d*)/', $expectedArgumentCount, $argMatch);
                        // print_r($argMatch);
                        // echo PHP_EOL;
                        switch ($argMatch[2]) {
                            case '+' :
                                if ($argumentCount < $argMatch[1]) {
                                    $argumentCountError = true;
                                    $expectedArgumentCountString = $argMatch[1] . ' or more ';
                                }
                                break;
                            case '-' :
                                if (($argumentCount < $argMatch[1]) || ($argumentCount > $argMatch[3])) {
                                    $argumentCountError = true;
                                    $expectedArgumentCountString = 'between ' . $argMatch[1] . ' and ' . $argMatch[3];
                                }
                                break;
                            case ',' :
                                if (($argumentCount != $argMatch[1]) && ($argumentCount != $argMatch[3])) {
                                    $argumentCountError = true;
                                    $expectedArgumentCountString = 'either ' . $argMatch[1] . ' or ' . $argMatch[3];
                                }
                                break;
                        }
                    }
                    if ($argumentCountError) {
                        return $this->raiseFormulaError("Formula Error: Wrong number of arguments for $functionName() function: $argumentCount given, " . $expectedArgumentCountString . " expected");
                    }
                }
                ++$index;
            } elseif ($opCharacter == ',') { // Is this the separator for function arguments?
                // echo 'Element is a Function argument separator', PHP_EOL;
                while ( ($o2 = $stack->pop()) && $o2['value'] != '(' ) { // Pop off the stack back to the last (
                    if ($o2 === null) {
                        return $this->raiseFormulaError("Formula Error: Unexpected ,");
                    } else {
                        $output[] = $o2; // pop the argument expression stuff and push onto the output
                    }
                }
                // If we've a comma when we're expecting an operand, then what we actually have is a null operand;
                // so push a null onto the stack
                if (($expectingOperand) || (!$expectingOperator)) {
                    $output[] = array(
                    'type' => 'NULL Value',
                    'value' => self::$excelConstants['NULL'],
                    'reference' => null 
                    );
                }
                // make sure there was a function
                $d = $stack->last(2);
                if (!preg_match('/^' . self::CALCULATION_REGEXP_FUNCTION . '$/i', $d['value'], $matches)) {
                    return $this->raiseFormulaError("Formula Error: Unexpected ,");
                }
                $d = $stack->pop();
                $stack->push($d['type'], ++$d['value'], $d['reference']); // increment the argument count
                $stack->push('Brace', '('); // put the ( back on, we'll need to pop back to it again
                $expectingOperator = false;
                $expectingOperand = true;
                ++$index;
            } elseif ($opCharacter == '(' && !$expectingOperator) {
                // echo 'Element is an Opening Bracket<br />';
                $stack->push('Brace', '(');
                ++$index;
            } elseif ($isOperandOrFunction && !$expectingOperator) { // do we now have a function/variable/number?
                $expectingOperator = true;
                $expectingOperand = false;
                $val = $match[1];
                $length = strlen($val);
                // echo 'Element with value '.$val.' is an Operand, Variable, Constant, String, Number, Cell Reference or Function<br />';
                

                if (preg_match('/^' . self::CALCULATION_REGEXP_FUNCTION . '$/i', $val, $matches)) {
                    $val = preg_replace('/\s/u', '', $val);
                    // echo 'Element '.$val.' is a Function<br />';
                    if (isset(self::$PHPExcelFunctions[strtoupper($matches[1])]) || isset(self::$controlFunctions[strtoupper($matches[1])])) { // it's a function
                        $stack->push('Function', strtoupper($val));
                        $ax = preg_match('/^\s*(\s*\))/ui', substr($formula, $index + $length), $amatch);
                        if ($ax) {
                            $stack->push('Operand Count for Function ' . strtoupper($val) . ')', 0);
                            $expectingOperator = true;
                        } else {
                            $stack->push('Operand Count for Function ' . strtoupper($val) . ')', 1);
                            $expectingOperator = false;
                        }
                        $stack->push('Brace', '(');
                    } else { // it's a var w/ implicit multiplication
                        $output[] = array(
                        'type' => 'Value',
                        'value' => $matches[1],
                        'reference' => null 
                        );
                    }
                } elseif (preg_match('/^' . self::CALCULATION_REGEXP_CELLREF . '$/i', $val, $matches)) {
                    // echo 'Element '.$val.' is a Cell reference<br />';
                    // Watch for this case-change when modifying to allow cell references in different worksheets...
                    // Should only be applied to the actual cell column, not the worksheet name
                    

                    // If the last entry on the stack was a : operator, then we have a cell range reference
                    $testPrevOp = $stack->last(1);
                    if ($testPrevOp['value'] == ':') {
                        // If we have a worksheet reference, then we're playing with a 3D reference
                        if ($matches[2] == '') {
                            // Otherwise, we 'inherit' the worksheet reference from the start cell reference
                            // The start of the cell range reference should be the last entry in $output
                            $startCellRef = $output[count($output) - 1]['value'];
                            preg_match('/^' . self::CALCULATION_REGEXP_CELLREF . '$/i', $startCellRef, $startMatches);
                            if ($startMatches[2] > '') {
                                $val = $startMatches[2] . '!' . $val;
                            }
                        } else {
                            return $this->raiseFormulaError("3D Range references are not yet supported");
                        }
                    }
                    
                    $output[] = array(
                    'type' => 'Cell Reference',
                    'value' => $val,
                    'reference' => $val 
                    );
                    // $expectingOperator = FALSE;
                } else { // it's a variable, constant, string, number or boolean
                    // echo 'Element is a Variable, Constant, String, Number or Boolean<br />';
                    // If the last entry on the stack was a : operator, then we may have a row or column range reference
                    $testPrevOp = $stack->last(1);
                    if ($testPrevOp['value'] == ':') {
                        $startRowColRef = $output[count($output) - 1]['value'];
                        $rangeWS1 = '';
                        if (strpos('!', $startRowColRef) !== false) {
                            list($rangeWS1, $startRowColRef) = explode('!', $startRowColRef);
                        }
                        if ($rangeWS1 != '') {
                            $rangeWS1 .= '!';
                        }
                        $rangeWS2 = $rangeWS1;
                        if (strpos('!', $val) !== false) {
                            list($rangeWS2, $val) = explode('!', $val);
                        }
                        if ($rangeWS2 != '') {
                            $rangeWS2 .= '!';
                        }
                        if ((is_integer($startRowColRef)) && (ctype_digit($val)) && ($startRowColRef <= 1048576) && ($val <= 1048576)) {
                            // Row range
                            $endRowColRef = ($pCellParent !== null) ? $pCellParent->getHighestColumn() : 'XFD'; // Max 16,384 columns for Excel2007
                            $output[count($output) - 1]['value'] = $rangeWS1 . 'A' . $startRowColRef;
                            $val = $rangeWS2 . $endRowColRef . $val;
                        } elseif ((ctype_alpha($startRowColRef)) && (ctype_alpha($val)) && (strlen($startRowColRef) <= 3) && (strlen($val) <= 3)) {
                            // Column range
                            $endRowColRef = ($pCellParent !== null) ? $pCellParent->getHighestRow() : 1048576; // Max 1,048,576 rows for Excel2007
                            $output[count($output) - 1]['value'] = $rangeWS1 . strtoupper($startRowColRef) . '1';
                            $val = $rangeWS2 . $val . $endRowColRef;
                        }
                    }
                    
                    $localeConstant = false;
                    if ($opCharacter == '"') {
                        // echo 'Element is a String<br />';
                        // UnEscape any quotes within the string
                        $val = self::wrapResult(str_replace('""', '"', self::unwrapResult($val)));
                    } elseif (is_numeric($val)) {
                        // echo 'Element is a Number<br />';
                        if ((strpos($val, '.') !== false) || (stripos($val, 'e') !== false) || ($val > PHP_INT_MAX) || ($val < -PHP_INT_MAX)) {
                            // echo 'Casting '.$val.' to float<br />';
                            $val = (float) $val;
                        } else {
                            // echo 'Casting '.$val.' to integer<br />';
                            $val = (integer) $val;
                        }
                    } elseif (isset(self::$excelConstants[trim(strtoupper($val))])) {
                        $excelConstant = trim(strtoupper($val));
                        // echo 'Element '.$excelConstant.' is an Excel Constant<br />';
                        $val = self::$excelConstants[$excelConstant];
                    } elseif (($localeConstant = array_search(trim(strtoupper($val)), self::$localeBoolean)) !== false) {
                        // echo 'Element '.$localeConstant.' is an Excel Constant<br />';
                        $val = self::$excelConstants[$localeConstant];
                    }
                    $details = array(
                    'type' => 'Value',
                    'value' => $val,
                    'reference' => null 
                    );
                    if ($localeConstant) {
                        $details['localeValue'] = $localeConstant;
                    }
                    $output[] = $details;
                }
                $index += $length;
            } elseif ($opCharacter == '$') { // absolute row or column range
                ++$index;
            } elseif ($opCharacter == ')') { // miscellaneous error checking
                if ($expectingOperand) {
                    $output[] = array(
                    'type' => 'NULL Value',
                    'value' => self::$excelConstants['NULL'],
                    'reference' => null 
                    );
                    $expectingOperand = false;
                    $expectingOperator = true;
                } else {
                    return $this->raiseFormulaError("Formula Error: Unexpected ')'");
                }
            } elseif (isset(self::$operators[$opCharacter]) && !$expectingOperator) {
                return $this->raiseFormulaError("Formula Error: Unexpected operator '$opCharacter'");
            } else { // I don't even want to know what you did to get here
                return $this->raiseFormulaError("Formula Error: An unexpected error occured");
            }
            // Test for end of formula string
            if ($index == strlen($formula)) {
                // Did we end with an operator?.
                // Only valid for the % unary operator
                if ((isset(self::$operators[$opCharacter])) && ($opCharacter != '%')) {
                    return $this->raiseFormulaError("Formula Error: Operator '$opCharacter' has no operands");
                } else {
                    break;
                }
            }
            // Ignore white space
            while ( ($formula{$index} == "\n") || ($formula{$index} == "\r") ) {
                ++$index;
            }
            if ($formula{$index} == ' ') {
                while ( $formula{$index} == ' ' ) {
                    ++$index;
                }
                // If we're expecting an operator, but only have a space between the previous and next operands (and both are
                // Cell References) then we have an INTERSECTION operator
                // echo 'Possible Intersect Operator<br />';
                if (($expectingOperator) && (preg_match('/^' . self::CALCULATION_REGEXP_CELLREF . '.*/Ui', substr($formula, $index), $match)) && ($output[count($output) - 1]['type'] == 'Cell Reference')) {
                    // echo 'Element is an Intersect Operator<br />';
                    while ( $stack->count() > 0 && ($o2 = $stack->last()) && isset(self::$operators[$o2['value']]) && @(self::$operatorAssociativity[$opCharacter] ? self::$operatorPrecedence[$opCharacter] < self::$operatorPrecedence[$o2['value']] : self::$operatorPrecedence[$opCharacter] <= self::$operatorPrecedence[$o2['value']]) ) {
                        $output[] = $stack->pop(); // Swap operands and higher precedence operators from the stack to the output
                    }
                    $stack->push('Binary Operator', '|'); // Put an Intersect Operator on the stack
                    $expectingOperator = false;
                }
            }
        }
        
        while ( ($op = $stack->pop()) !== null ) { // pop everything off the stack and push onto output
            if ((is_array($op) && $op['value'] == '(') || ($op === '(')) {
                return $this->raiseFormulaError("Formula Error: Expecting ')'"); // if there are any opening braces on the stack, then braces were unbalanced
            }
            $output[] = $op;
        }
        return $output;
    }
    private static function dataTestReference(&$operandData) {
        $operand = $operandData['value'];
        if (($operandData['reference'] === null) && (is_array($operand))) {
            $rKeys = array_keys($operand);
            $rowKey = array_shift($rKeys);
            $cKeys = array_keys(array_keys($operand[$rowKey]));
            $colKey = array_shift($cKeys);
            if (ctype_upper($colKey)) {
                $operandData['reference'] = $colKey . $rowKey;
            }
        }
        return $operand;
    }
    
    // evaluate postfix notation
    private function processTokenStack($tokens, $cellID = null, Cell $pCell = null) {
        if ($tokens == false) {
            return false;
        }
        
        // If we're using cell caching, then $pCell may well be flushed back to the cache (which detaches the parent cell collection),
        // so we store the parent cell collection so that we can re-attach it when necessary
        $pCellWorksheet = ($pCell !== null) ? $pCell->getWorksheet() : null;
        $pCellParent = ($pCell !== null) ? $pCell->getParent() : null;
        $stack = new Calculation\Token\Stack();
        
        // Loop through each token in turn
        foreach ( $tokens as $tokenData ) {
            // print_r($tokenData);
            // echo '<br />';
            $token = $tokenData['value'];
            // echo '<b>Token is '.$token.'</b><br />';
            // if the token is a binary operator, pop the top two values off the stack, do the operation, and push the result back on the stack
            if (isset(self::$binaryOperators[$token])) {
                // echo 'Token is a binary operator<br />';
                // We must have two operands, error if we don't
                if (($operand2Data = $stack->pop()) === null) {
                    return $this->raiseFormulaError('Internal error - Operand value missing from stack');
                }
                if (($operand1Data = $stack->pop()) === null) {
                    return $this->raiseFormulaError('Internal error - Operand value missing from stack');
                }
                
                $operand1 = self::dataTestReference($operand1Data);
                $operand2 = self::dataTestReference($operand2Data);
                
                // Log what we're doing
                if ($token == ':') {
                    $this->_debugLog->writeDebugLog('Evaluating Range ', $this->showValue($operand1Data['reference']), ' ', $token, ' ', $this->showValue($operand2Data['reference']));
                } else {
                    $this->_debugLog->writeDebugLog('Evaluating ', $this->showValue($operand1), ' ', $token, ' ', $this->showValue($operand2));
                }
                
                // Process the operation in the appropriate manner
                switch ($token) {
                    // Comparison (Boolean) Operators
                    case '>' : // Greater than
                    case '<' : // Less than
                    case '>=' : // Greater than or Equal to
                    case '<=' : // Less than or Equal to
                    case '=' : // Equality
                    case '<>' : // Inequality
                        $this->executeBinaryComparisonOperation($cellID, $operand1, $operand2, $token, $stack);
                        break;
                    // Binary Operators
                    case ':' : // Range
                        $sheet1 = $sheet2 = '';
                        if (strpos($operand1Data['reference'], '!') !== false) {
                            list($sheet1, $operand1Data['reference']) = explode('!', $operand1Data['reference']);
                        } else {
                            $sheet1 = ($pCellParent !== null) ? $pCellWorksheet->getTitle() : '';
                        }
                        if (strpos($operand2Data['reference'], '!') !== false) {
                            list($sheet2, $operand2Data['reference']) = explode('!', $operand2Data['reference']);
                        } else {
                            $sheet2 = $sheet1;
                        }
                        if ($sheet1 == $sheet2) {
                            if ($operand1Data['reference'] === null) {
                                if ((trim($operand1Data['value']) != '') && (is_numeric($operand1Data['value']))) {
                                    $operand1Data['reference'] = $pCell->getColumn() . $operand1Data['value'];
                                } elseif (trim($operand1Data['reference']) == '') {
                                    $operand1Data['reference'] = $pCell->getCoordinate();
                                } else {
                                    $operand1Data['reference'] = $operand1Data['value'] . $pCell->getRow();
                                }
                            }
                            if ($operand2Data['reference'] === null) {
                                if ((trim($operand2Data['value']) != '') && (is_numeric($operand2Data['value']))) {
                                    $operand2Data['reference'] = $pCell->getColumn() . $operand2Data['value'];
                                } elseif (trim($operand2Data['reference']) == '') {
                                    $operand2Data['reference'] = $pCell->getCoordinate();
                                } else {
                                    $operand2Data['reference'] = $operand2Data['value'] . $pCell->getRow();
                                }
                            }
                            
                            $oData = array_merge(explode(':', $operand1Data['reference']), explode(':', $operand2Data['reference']));
                            $oCol = $oRow = array();
                            foreach ( $oData as $oDatum ) {
                                $oCR = Cell::coordinateFromString($oDatum);
                                $oCol[] = Cell::columnIndexFromString($oCR[0]) - 1;
                                $oRow[] = $oCR[1];
                            }
                            $cellRef = Cell::stringFromColumnIndex(min($oCol)) . min($oRow) . ':' . Cell::stringFromColumnIndex(max($oCol)) . max($oRow);
                            if ($pCellParent !== null) {
                                $cellValue = $this->extractCellRange($cellRef, $this->spreadsheet->getSheetByName($sheet1), false);
                            } else {
                                return $this->raiseFormulaError('Unable to access Cell Reference');
                            }
                            $stack->push('Cell Reference', $cellValue, $cellRef);
                        } else {
                            $stack->push('Error', Calculation\Functions::REF(), null);
                        }
                        break;
                    case '+' : // Addition
                        $this->executeNumericBinaryOperation($cellID, $operand1, $operand2, $token, 'plusEquals', $stack);
                        break;
                    case '-' : // Subtraction
                        $this->executeNumericBinaryOperation($cellID, $operand1, $operand2, $token, 'minusEquals', $stack);
                        break;
                    case '*' : // Multiplication
                        $this->executeNumericBinaryOperation($cellID, $operand1, $operand2, $token, 'arrayTimesEquals', $stack);
                        break;
                    case '/' : // Division
                        $this->executeNumericBinaryOperation($cellID, $operand1, $operand2, $token, 'arrayRightDivide', $stack);
                        break;
                    case '^' : // Exponential
                        $this->executeNumericBinaryOperation($cellID, $operand1, $operand2, $token, 'power', $stack);
                        break;
                    case '&' : // Concatenation
                        // If either of the operands is a matrix, we need to treat them both as matrices
                        // (converting the other operand to a matrix if need be); then perform the required
                        // matrix operation
                        if (is_bool($operand1)) {
                            $operand1 = ($operand1) ? self::$localeBoolean['TRUE'] : self::$localeBoolean['FALSE'];
                        }
                        if (is_bool($operand2)) {
                            $operand2 = ($operand2) ? self::$localeBoolean['TRUE'] : self::$localeBoolean['FALSE'];
                        }
                        if ((is_array($operand1)) || (is_array($operand2))) {
                            // Ensure that both operands are arrays/matrices
                            self::checkMatrixOperands($operand1, $operand2, 2);
                            try {
                                // Convert operand 1 from a PHP array to a matrix
                                $matrix = new Shared\JAMA\Matrix($operand1);
                                // Perform the required operation against the operand 1 matrix, passing in operand 2
                                $matrixResult = $matrix->concat($operand2);
                                $result = $matrixResult->getArray();
                            } catch ( Exception $ex ) {
                                $this->_debugLog->writeDebugLog('JAMA Matrix Exception: ', $ex->getMessage());
                                $result = '#VALUE!';
                            }
                        } else {
                            $result = '"' . str_replace('""', '"', self::unwrapResult($operand1, '"') . self::unwrapResult($operand2, '"')) . '"';
                        }
                        $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($result));
                        $stack->push('Value', $result);
                        break;
                    case '|' : // Intersect
                        $rowIntersect = array_intersect_key($operand1, $operand2);
                        $cellIntersect = $oCol = $oRow = array();
                        foreach ( array_keys($rowIntersect) as $row ) {
                            $oRow[] = $row;
                            foreach ( $rowIntersect[$row] as $col => $data ) {
                                $oCol[] = Cell::columnIndexFromString($col) - 1;
                                $cellIntersect[$row] = array_intersect_key($operand1[$row], $operand2[$row]);
                            }
                        }
                        $cellRef = Cell::stringFromColumnIndex(min($oCol)) . min($oRow) . ':' . Cell::stringFromColumnIndex(max($oCol)) . max($oRow);
                        $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($cellIntersect));
                        $stack->push('Value', $cellIntersect, $cellRef);
                        break;
                }
                
                // if the token is a unary operator, pop one value off the stack, do the operation, and push it back on
            } elseif (($token === '~') || ($token === '%')) {
                // echo 'Token is a unary operator<br />';
                if (($arg = $stack->pop()) === null) {
                    return $this->raiseFormulaError('Internal error - Operand value missing from stack');
                }
                $arg = $arg['value'];
                if ($token === '~') {
                    // echo 'Token is a negation operator<br />';
                    $this->_debugLog->writeDebugLog('Evaluating Negation of ', $this->showValue($arg));
                    $multiplier = -1;
                } else {
                    // echo 'Token is a percentile operator<br />';
                    $this->_debugLog->writeDebugLog('Evaluating Percentile of ', $this->showValue($arg));
                    $multiplier = 0.01;
                }
                if (is_array($arg)) {
                    self::checkMatrixOperands($arg, $multiplier, 2);
                    try {
                        $matrix1 = new Shared\JAMA\Matrix($arg);
                        $matrixResult = $matrix1->arrayTimesEquals($multiplier);
                        $result = $matrixResult->getArray();
                    } catch ( Exception $ex ) {
                        $this->_debugLog->writeDebugLog('JAMA Matrix Exception: ', $ex->getMessage());
                        $result = '#VALUE!';
                    }
                    $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($result));
                    $stack->push('Value', $result);
                } else {
                    $this->executeNumericBinaryOperation($cellID, $multiplier, $arg, '*', 'arrayTimesEquals', $stack);
                }
            } elseif (preg_match('/^' . self::CALCULATION_REGEXP_CELLREF . '$/i', $token, $matches)) {
                $cellRef = null;
                // echo 'Element '.$token.' is a Cell reference<br />';
                if (isset($matches[8])) {
                    // echo 'Reference is a Range of cells<br />';
                    if ($pCell === null) {
                        // We can't access the range, so return a REF error
                        $cellValue = Calculation\Functions::REF();
                    } else {
                        $cellRef = $matches[6] . $matches[7] . ':' . $matches[9] . $matches[10];
                        if ($matches[2] > '') {
                            $matches[2] = trim($matches[2], "\"'");
                            if ((strpos($matches[2], '[') !== false) || (strpos($matches[2], ']') !== false)) {
                                // It's a Reference to an external spreadsheet (not currently supported)
                                return $this->raiseFormulaError('Unable to access External Workbook');
                            }
                            $matches[2] = trim($matches[2], "\"'");
                            // echo '$cellRef='.$cellRef.' in worksheet '.$matches[2].'<br />';
                            $this->_debugLog->writeDebugLog('Evaluating Cell Range ', $cellRef, ' in worksheet ', $matches[2]);
                            if ($pCellParent !== null) {
                                $cellValue = $this->extractCellRange($cellRef, $this->spreadsheet->getSheetByName($matches[2]), false);
                            } else {
                                return $this->raiseFormulaError('Unable to access Cell Reference');
                            }
                            $this->_debugLog->writeDebugLog('Evaluation Result for cells ', $cellRef, ' in worksheet ', $matches[2], ' is ', $this->showTypeDetails($cellValue));
                            // $cellRef = $matches[2].'!'.$cellRef;
                        } else {
                            // echo '$cellRef='.$cellRef.' in current worksheet<br />';
                            $this->_debugLog->writeDebugLog('Evaluating Cell Range ', $cellRef, ' in current worksheet');
                            if ($pCellParent !== null) {
                                $cellValue = $this->extractCellRange($cellRef, $pCellWorksheet, false);
                            } else {
                                return $this->raiseFormulaError('Unable to access Cell Reference');
                            }
                            $this->_debugLog->writeDebugLog('Evaluation Result for cells ', $cellRef, ' is ', $this->showTypeDetails($cellValue));
                        }
                    }
                } else {
                    // echo 'Reference is a single Cell<br />';
                    if ($pCell === null) {
                        // We can't access the cell, so return a REF error
                        $cellValue = Calculation\Functions::REF();
                    } else {
                        $cellRef = $matches[6] . $matches[7];
                        if ($matches[2] > '') {
                            $matches[2] = trim($matches[2], "\"'");
                            if ((strpos($matches[2], '[') !== false) || (strpos($matches[2], ']') !== false)) {
                                // It's a Reference to an external spreadsheet (not currently supported)
                                return $this->raiseFormulaError('Unable to access External Workbook');
                            }
                            // echo '$cellRef='.$cellRef.' in worksheet '.$matches[2].'<br />';
                            $this->_debugLog->writeDebugLog('Evaluating Cell ', $cellRef, ' in worksheet ', $matches[2]);
                            if ($pCellParent !== null) {
                                $cellSheet = $this->spreadsheet->getSheetByName($matches[2]);
                                if ($cellSheet && $cellSheet->cellExists($cellRef)) {
                                    $cellValue = $this->extractCellRange($cellRef, $this->spreadsheet->getSheetByName($matches[2]), false);
                                    $pCell->attach($pCellParent);
                                } else {
                                    $cellValue = null;
                                }
                            } else {
                                return $this->raiseFormulaError('Unable to access Cell Reference');
                            }
                            $this->_debugLog->writeDebugLog('Evaluation Result for cell ', $cellRef, ' in worksheet ', $matches[2], ' is ', $this->showTypeDetails($cellValue));
                            // $cellRef = $matches[2].'!'.$cellRef;
                        } else {
                            // echo '$cellRef='.$cellRef.' in current worksheet<br />';
                            $this->_debugLog->writeDebugLog('Evaluating Cell ', $cellRef, ' in current worksheet');
                            if ($pCellParent->isDataSet($cellRef)) {
                                $cellValue = $this->extractCellRange($cellRef, $pCellWorksheet, false);
                                $pCell->attach($pCellParent);
                            } else {
                                $cellValue = null;
                            }
                            $this->_debugLog->writeDebugLog('Evaluation Result for cell ', $cellRef, ' is ', $this->showTypeDetails($cellValue));
                        }
                    }
                }
                $stack->push('Value', $cellValue, $cellRef);
                
                // if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on
            } elseif (preg_match('/^' . self::CALCULATION_REGEXP_FUNCTION . '$/i', $token, $matches)) {
                // echo 'Token is a function<br />';
                $functionName = $matches[1];
                $argCount = $stack->pop();
                $argCount = $argCount['value'];
                if ($functionName != 'MKMATRIX') {
                    $this->_debugLog->writeDebugLog('Evaluating Function ', self::localeFunc($functionName), '() with ', (($argCount == 0) ? 'no' : $argCount), ' argument', (($argCount == 1) ? '' : 's'));
                }
                if ((isset(self::$PHPExcelFunctions[$functionName])) || (isset(self::$controlFunctions[$functionName]))) { // function
                    if (isset(self::$PHPExcelFunctions[$functionName])) {
                        $functionCall = self::$PHPExcelFunctions[$functionName]['functionCall'];
                        $passByReference = isset(self::$PHPExcelFunctions[$functionName]['passByReference']);
                        $passCellReference = isset(self::$PHPExcelFunctions[$functionName]['passCellReference']);
                    } elseif (isset(self::$controlFunctions[$functionName])) {
                        $functionCall = self::$controlFunctions[$functionName]['functionCall'];
                        $passByReference = isset(self::$controlFunctions[$functionName]['passByReference']);
                        $passCellReference = isset(self::$controlFunctions[$functionName]['passCellReference']);
                    }
                    // get the arguments for this function
                    // echo 'Function '.$functionName.' expects '.$argCount.' arguments<br />';
                    $args = $argArrayVals = array();
                    for($i = 0; $i < $argCount; ++$i) {
                        $arg = $stack->pop();
                        $a = $argCount - $i - 1;
                        if (($passByReference) && (isset(self::$PHPExcelFunctions[$functionName]['passByReference'][$a])) && (self::$PHPExcelFunctions[$functionName]['passByReference'][$a])) {
                            if ($arg['reference'] === null) {
                                $args[] = $cellID;
                                if ($functionName != 'MKMATRIX') {
                                    $argArrayVals[] = $this->showValue($cellID);
                                }
                            } else {
                                $args[] = $arg['reference'];
                                if ($functionName != 'MKMATRIX') {
                                    $argArrayVals[] = $this->showValue($arg['reference']);
                                }
                            }
                        } else {
                            $args[] = self::unwrapResult($arg['value']);
                            if ($functionName != 'MKMATRIX') {
                                $argArrayVals[] = $this->showValue($arg['value']);
                            }
                        }
                    }
                    // Reverse the order of the arguments
                    krsort($args);
                    if (($passByReference) && ($argCount == 0)) {
                        $args[] = $cellID;
                        $argArrayVals[] = $this->showValue($cellID);
                    }
                    // echo 'Arguments are: ';
                    // print_r($args);
                    // echo '<br />';
                    if ($functionName != 'MKMATRIX') {
                        if ($this->_debugLog->getWriteDebugLog()) {
                            krsort($argArrayVals);
                            $this->_debugLog->writeDebugLog('Evaluating ', self::localeFunc($functionName), '( ', implode(self::$localeArgumentSeparator . ' ', Calculation\Functions::flattenArray($argArrayVals)), ' )');
                        }
                    }
                    // Process each argument in turn, building the return value as an array
                    // if (($argCount == 1) && (is_array($args[1])) && ($functionName != 'MKMATRIX')) {
                    // $operand1 = $args[1];
                    // $this->_debugLog->writeDebugLog('Argument is a matrix: ', $this->showValue($operand1));
                    // $result = array();
                    // $row = 0;
                    // foreach($operand1 as $args) {
                    // if (is_array($args)) {
                    // foreach($args as $arg) {
                    // $this->_debugLog->writeDebugLog('Evaluating ', self::localeFunc($functionName), '( ', $this->showValue($arg), ' )');
                    // $r = call_user_func_array($functionCall, $arg);
                    // $this->_debugLog->writeDebugLog('Evaluation Result for ', self::localeFunc($functionName), '() function call is ', $this->showTypeDetails($r));
                    // $result[$row][] = $r;
                    // }
                    // ++$row;
                    // } else {
                    // $this->_debugLog->writeDebugLog('Evaluating ', self::localeFunc($functionName), '( ', $this->showValue($args), ' )');
                    // $r = call_user_func_array($functionCall, $args);
                    // $this->_debugLog->writeDebugLog('Evaluation Result for ', self::localeFunc($functionName), '() function call is ', $this->showTypeDetails($r));
                    // $result[] = $r;
                    // }
                    // }
                    // } else {
                    // Process the argument with the appropriate function call
                    if ($passCellReference) {
                        $args[] = $pCell;
                    }
                    if (strpos($functionCall, '::') !== false) {
                        $result = call_user_func_array(explode('::', $functionCall), $args);
                    } else {
                        foreach ( $args as &$arg ) {
                            $arg = Calculation\Functions::flattenSingleValue($arg);
                        }
                        unset($arg);
                        $result = call_user_func_array($functionCall, $args);
                    }
                    if ($functionName != 'MKMATRIX') {
                        $this->_debugLog->writeDebugLog('Evaluation Result for ', self::localeFunc($functionName), '() function call is ', $this->showTypeDetails($result));
                    }
                    $stack->push('Value', self::wrapResult($result));
                }
            } else {
                // if the token is a number, boolean, string or an Excel error, push it onto the stack
                if (isset(self::$excelConstants[strtoupper($token)])) {
                    $excelConstant = strtoupper($token);
                    // echo 'Token is a PHPExcel constant: '.$excelConstant.'<br />';
                    $stack->push('Constant Value', self::$excelConstants[$excelConstant]);
                    $this->_debugLog->writeDebugLog('Evaluating Constant ', $excelConstant, ' as ', $this->showTypeDetails(self::$excelConstants[$excelConstant]));
                } elseif ((is_numeric($token)) || ($token === null) || (is_bool($token)) || ($token == '') || ($token{0} == '"') || ($token{0} == '#')) {
                    // echo 'Token is a number, boolean, string, null or an Excel error<br />';
                    $stack->push('Value', $token);
                    // if the token is a named range, push the named range name onto the stack
                } elseif (preg_match('/^' . self::CALCULATION_REGEXP_NAMEDRANGE . '$/i', $token, $matches)) {
                    // echo 'Token is a named range<br />';
                    $namedRange = $matches[6];
                    // echo 'Named Range is '.$namedRange.'<br />';
                    $this->_debugLog->writeDebugLog('Evaluating Named Range ', $namedRange);
                    $cellValue = $this->extractNamedRange($namedRange, ((null !== $pCell) ? $pCellWorksheet : null), false);
                    $pCell->attach($pCellParent);
                    $this->_debugLog->writeDebugLog('Evaluation Result for named range ', $namedRange, ' is ', $this->showTypeDetails($cellValue));
                    $stack->push('Named Range', $cellValue, $namedRange);
                } else {
                    return $this->raiseFormulaError("undefined variable '$token'");
                }
            }
        }
        // when we're out of tokens, the stack should have a single element, the final result
        if ($stack->count() != 1) {
            return $this->raiseFormulaError("internal error");
        }
        $output = $stack->pop();
        $output = $output['value'];
        
        // if ((is_array($output)) && (self::$returnArrayAsType != self::RETURN_ARRAY_AS_ARRAY)) {
        // return array_shift(Calculation\Functions::flattenArray($output));
        // }
        return $output;
    }
    private function validateBinaryOperand($cellID, &$operand, &$stack) {
        if (is_array($operand)) {
            if ((count($operand, COUNT_RECURSIVE) - count($operand)) == 1) {
                do {
                    $operand = array_pop($operand);
                } while ( is_array($operand) );
            }
        }
        // Numbers, matrices and booleans can pass straight through, as they're already valid
        if (is_string($operand)) {
            // We only need special validations for the operand if it is a string
            // Start by stripping off the quotation marks we use to identify true excel string values internally
            if ($operand > '' && $operand{0} == '"') {
                $operand = self::unwrapResult($operand);
            }
            // If the string is a numeric value, we treat it as a numeric, so no further testing
            if (!is_numeric($operand)) {
                // If not a numeric, test to see if the value is an Excel error, and so can't be used in normal binary operations
                if ($operand > '' && $operand{0} == '#') {
                    $stack->push('Value', $operand);
                    $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($operand));
                    return false;
                } elseif (!Shared\StringHelper::convertToNumberIfFraction($operand)) {
                    // If not a numeric or a fraction, then it's a text string, and so can't be used in mathematical binary operations
                    $stack->push('Value', '#VALUE!');
                    $this->_debugLog->writeDebugLog('Evaluation Result is a ', $this->showTypeDetails('#VALUE!'));
                    return false;
                }
            }
        }
        
        // return a true if the value of the operand is one that we can use in normal binary operations
        return true;
    }
    private function executeBinaryComparisonOperation($cellID, $operand1, $operand2, $operation, &$stack, $recursingArrays = false) {
        // If we're dealing with matrix operations, we want a matrix result
        if ((is_array($operand1)) || (is_array($operand2))) {
            $result = array();
            if ((is_array($operand1)) && (!is_array($operand2))) {
                foreach ( $operand1 as $x => $operandData ) {
                    $this->_debugLog->writeDebugLog('Evaluating Comparison ', $this->showValue($operandData), ' ', $operation, ' ', $this->showValue($operand2));
                    $this->executeBinaryComparisonOperation($cellID, $operandData, $operand2, $operation, $stack);
                    $r = $stack->pop();
                    $result[$x] = $r['value'];
                }
            } elseif ((!is_array($operand1)) && (is_array($operand2))) {
                foreach ( $operand2 as $x => $operandData ) {
                    $this->_debugLog->writeDebugLog('Evaluating Comparison ', $this->showValue($operand1), ' ', $operation, ' ', $this->showValue($operandData));
                    $this->executeBinaryComparisonOperation($cellID, $operand1, $operandData, $operation, $stack);
                    $r = $stack->pop();
                    $result[$x] = $r['value'];
                }
            } else {
                if (!$recursingArrays) {
                    self::checkMatrixOperands($operand1, $operand2, 2);
                }
                foreach ( $operand1 as $x => $operandData ) {
                    $this->_debugLog->writeDebugLog('Evaluating Comparison ', $this->showValue($operandData), ' ', $operation, ' ', $this->showValue($operand2[$x]));
                    $this->executeBinaryComparisonOperation($cellID, $operandData, $operand2[$x], $operation, $stack, true);
                    $r = $stack->pop();
                    $result[$x] = $r['value'];
                }
            }
            // Log the result details
            $this->_debugLog->writeDebugLog('Comparison Evaluation Result is ', $this->showTypeDetails($result));
            // And push the result onto the stack
            $stack->push('Array', $result);
            return true;
        }
        
        // Simple validate the two operands if they are string values
        if (is_string($operand1) && $operand1 > '' && $operand1{0} == '"') {
            $operand1 = self::unwrapResult($operand1);
        }
        if (is_string($operand2) && $operand2 > '' && $operand2{0} == '"') {
            $operand2 = self::unwrapResult($operand2);
        }
        
        // Use case insensitive comparaison if not OpenOffice mode
        if (Calculation\Functions::getCompatibilityMode() != Calculation\Functions::COMPATIBILITY_OPENOFFICE) {
            if (is_string($operand1)) {
                $operand1 = strtoupper($operand1);
            }
            if (is_string($operand2)) {
                $operand2 = strtoupper($operand2);
            }
        }
        
        $useLowercaseFirstComparison = is_string($operand1) && is_string($operand2) && Calculation\Functions::getCompatibilityMode() == Calculation\Functions::COMPATIBILITY_OPENOFFICE;
        
        // execute the necessary operation
        switch ($operation) {
            // Greater than
            case '>' :
                if ($useLowercaseFirstComparison) {
                    $result = $this->strcmpLowercaseFirst($operand1, $operand2) > 0;
                } else {
                    $result = ($operand1 > $operand2);
                }
                break;
            // Less than
            case '<' :
                if ($useLowercaseFirstComparison) {
                    $result = $this->strcmpLowercaseFirst($operand1, $operand2) < 0;
                } else {
                    $result = ($operand1 < $operand2);
                }
                break;
            // Equality
            case '=' :
                if (is_numeric($operand1) && is_numeric($operand2)) {
                    $result = (abs($operand1 - $operand2) < $this->delta);
                } else {
                    $result = strcmp($operand1, $operand2) == 0;
                }
                break;
            // Greater than or equal
            case '>=' :
                if (is_numeric($operand1) && is_numeric($operand2)) {
                    $result = ((abs($operand1 - $operand2) < $this->delta) || ($operand1 > $operand2));
                } elseif ($useLowercaseFirstComparison) {
                    $result = $this->strcmpLowercaseFirst($operand1, $operand2) >= 0;
                } else {
                    $result = strcmp($operand1, $operand2) >= 0;
                }
                break;
            // Less than or equal
            case '<=' :
                if (is_numeric($operand1) && is_numeric($operand2)) {
                    $result = ((abs($operand1 - $operand2) < $this->delta) || ($operand1 < $operand2));
                } elseif ($useLowercaseFirstComparison) {
                    $result = $this->strcmpLowercaseFirst($operand1, $operand2) <= 0;
                } else {
                    $result = strcmp($operand1, $operand2) <= 0;
                }
                break;
            // Inequality
            case '<>' :
                if (is_numeric($operand1) && is_numeric($operand2)) {
                    $result = (abs($operand1 - $operand2) > 1E-14);
                } else {
                    $result = strcmp($operand1, $operand2) != 0;
                }
                break;
        }
        
        // Log the result details
        $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($result));
        // And push the result onto the stack
        $stack->push('Value', $result);
        return true;
    }
    
    /**
     * Compare two strings in the same way as strcmp() except that lowercase come before uppercase letters
     * 
     * @param string $str1
     *            First string value for the comparison
     * @param string $str2
     *            Second string value for the comparison
     * @return integer
     */
    private function strcmpLowercaseFirst($str1, $str2) {
        $inversedStr1 = Shared\StringHelper::strCaseReverse($str1);
        $inversedStr2 = Shared\StringHelper::strCaseReverse($str2);
        
        return strcmp($inversedStr1, $inversedStr2);
    }
    private function executeNumericBinaryOperation($cellID, $operand1, $operand2, $operation, $matrixFunction, &$stack) {
        // Validate the two operands
        if (!$this->validateBinaryOperand($cellID, $operand1, $stack)) {
            return false;
        }
        if (!$this->validateBinaryOperand($cellID, $operand2, $stack)) {
            return false;
        }
        
        // If either of the operands is a matrix, we need to treat them both as matrices
        // (converting the other operand to a matrix if need be); then perform the required
        // matrix operation
        if ((is_array($operand1)) || (is_array($operand2))) {
            // Ensure that both operands are arrays/matrices of the same size
            self::checkMatrixOperands($operand1, $operand2, 2);
            
            try {
                // Convert operand 1 from a PHP array to a matrix
                $matrix = new Shared\JAMA\Matrix($operand1);
                // Perform the required operation against the operand 1 matrix, passing in operand 2
                $matrixResult = $matrix->$matrixFunction($operand2);
                $result = $matrixResult->getArray();
            } catch ( Exception $ex ) {
                $this->_debugLog->writeDebugLog('JAMA Matrix Exception: ', $ex->getMessage());
                $result = '#VALUE!';
            }
        } else {
            if ((Calculation\Functions::getCompatibilityMode() != Calculation\Functions::COMPATIBILITY_OPENOFFICE) && ((is_string($operand1) && !is_numeric($operand1) && strlen($operand1) > 0) || (is_string($operand2) && !is_numeric($operand2) && strlen($operand2) > 0))) {
                $result = Calculation\Functions::VALUE();
            } else {
                // If we're dealing with non-matrix operations, execute the necessary operation
                switch ($operation) {
                    // Addition
                    case '+' :
                        $result = $operand1 + $operand2;
                        break;
                    // Subtraction
                    case '-' :
                        $result = $operand1 - $operand2;
                        break;
                    // Multiplication
                    case '*' :
                        $result = $operand1 * $operand2;
                        break;
                    // Division
                    case '/' :
                        if ($operand2 == 0) {
                            // Trap for Divide by Zero error
                            $stack->push('Value', '#DIV/0!');
                            $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails('#DIV/0!'));
                            return false;
                        } else {
                            $result = $operand1 / $operand2;
                        }
                        break;
                    // Power
                    case '^' :
                        $result = pow($operand1, $operand2);
                        break;
                }
            }
        }
        
        // Log the result details
        $this->_debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($result));
        // And push the result onto the stack
        $stack->push('Value', $result);
        return true;
    }
    
    // trigger an error, but nicely, if need be
    protected function raiseFormulaError($errorMessage) {
        $this->formulaError = $errorMessage;
        $this->cyclicReferenceStack->clear();
        if (!$this->suppressFormulaErrors) {
            throw new Calculation\Exception($errorMessage);
        }
        trigger_error($errorMessage, E_USER_ERROR);
    }
    
    /**
     * Extract range values
     *
     * @param
     *            string &$pRange String based range representation
     * @param Worksheet $pSheet
     *            Worksheet
     * @param boolean $resetLog
     *            Flag indicating whether calculation log should be reset or not
     * @return mixed Array of values in range if range contains more than one element. Otherwise, a single value is returned.
     * @throws Calculation\Exception
     */
    public function extractCellRange(&$pRange = 'A1', Worksheet $pSheet = null, $resetLog = true) {
        // Return value
        $returnValue = array();
        
        // echo 'extractCellRange('.$pRange.')', PHP_EOL;
        if ($pSheet !== null) {
            $pSheetName = $pSheet->getTitle();
            // echo 'Passed sheet name is '.$pSheetName.PHP_EOL;
            // echo 'Range reference is '.$pRange.PHP_EOL;
            if (strpos($pRange, '!') !== false) {
                // echo '$pRange reference includes sheet reference', PHP_EOL;
                list($pSheetName, $pRange) = Worksheet::extractSheetTitle($pRange, true);
                // echo 'New sheet name is '.$pSheetName, PHP_EOL;
                // echo 'Adjusted Range reference is '.$pRange, PHP_EOL;
                $pSheet = $this->spreadsheet->getSheetByName($pSheetName);
            }
            
            // Extract range
            $aReferences = Cell::extractAllCellReferencesInRange($pRange);
            $pRange = $pSheetName . '!' . $pRange;
            if (!isset($aReferences[1])) {
                // Single cell in range
                sscanf($aReferences[0], '%[A-Z]%d', $currentCol, $currentRow);
                $cellValue = null;
                if ($pSheet->cellExists($aReferences[0])) {
                    $returnValue[$currentRow][$currentCol] = $pSheet->getCell($aReferences[0])->getCalculatedValue($resetLog);
                } else {
                    $returnValue[$currentRow][$currentCol] = null;
                }
            } else {
                // Extract cell data for all cells in the range
                foreach ( $aReferences as $reference ) {
                    // Extract range
                    sscanf($reference, '%[A-Z]%d', $currentCol, $currentRow);
                    $cellValue = null;
                    if ($pSheet->cellExists($reference)) {
                        $returnValue[$currentRow][$currentCol] = $pSheet->getCell($reference)->getCalculatedValue($resetLog);
                    } else {
                        $returnValue[$currentRow][$currentCol] = null;
                    }
                }
            }
        }
        
        return $returnValue;
    }
    
    /**
     * Extract range values
     *
     * @param
     *            string &$pRange String based range representation
     * @param Worksheet $pSheet
     *            Worksheet
     * @return mixed Array of values in range if range contains more than one element. Otherwise, a single value is returned.
     * @param boolean $resetLog
     *            Flag indicating whether calculation log should be reset or not
     * @throws Calculation\Exception
     */
    public function extractNamedRange(&$pRange = 'A1', Worksheet $pSheet = null, $resetLog = true) {
        // Return value
        $returnValue = array();
        
        // echo 'extractNamedRange('.$pRange.')<br />';
        if ($pSheet !== null) {
            $pSheetName = $pSheet->getTitle();
            // echo 'Current sheet name is '.$pSheetName.'<br />';
            // echo 'Range reference is '.$pRange.'<br />';
            if (strpos($pRange, '!') !== false) {
                // echo '$pRange reference includes sheet reference', PHP_EOL;
                list($pSheetName, $pRange) = Worksheet::extractSheetTitle($pRange, true);
                // echo 'New sheet name is '.$pSheetName, PHP_EOL;
                // echo 'Adjusted Range reference is '.$pRange, PHP_EOL;
                $pSheet = $this->spreadsheet->getSheetByName($pSheetName);
            }
            
            // Named range?
            $namedRange = NamedRange::resolveRange($pRange, $pSheet);
            if ($namedRange !== null) {
                $pSheet = $namedRange->getWorksheet();
                // echo 'Named Range '.$pRange.' (';
                $pRange = $namedRange->getRange();
                $splitRange = Cell::splitRange($pRange);
                // Convert row and column references
                if (ctype_alpha($splitRange[0][0])) {
                    $pRange = $splitRange[0][0] . '1:' . $splitRange[0][1] . $namedRange->getWorksheet()->getHighestRow();
                } elseif (ctype_digit($splitRange[0][0])) {
                    $pRange = 'A' . $splitRange[0][0] . ':' . $namedRange->getWorksheet()->getHighestColumn() . $splitRange[0][1];
                }
                // echo $pRange.') is in sheet '.$namedRange->getWorksheet()->getTitle().'<br />';
                

                // if ($pSheet->getTitle() != $namedRange->getWorksheet()->getTitle()) {
                // if (!$namedRange->getLocalOnly()) {
                // $pSheet = $namedRange->getWorksheet();
                // } else {
                // return $returnValue;
                // }
                // }
            } else {
                return Calculation\Functions::REF();
            }
            
            // Extract range
            $aReferences = Cell::extractAllCellReferencesInRange($pRange);
            // var_dump($aReferences);
            if (!isset($aReferences[1])) {
                // Single cell (or single column or row) in range
                list($currentCol, $currentRow) = Cell::coordinateFromString($aReferences[0]);
                $cellValue = null;
                if ($pSheet->cellExists($aReferences[0])) {
                    $returnValue[$currentRow][$currentCol] = $pSheet->getCell($aReferences[0])->getCalculatedValue($resetLog);
                } else {
                    $returnValue[$currentRow][$currentCol] = null;
                }
            } else {
                // Extract cell data for all cells in the range
                foreach ( $aReferences as $reference ) {
                    // Extract range
                    list($currentCol, $currentRow) = Cell::coordinateFromString($reference);
                    // echo 'NAMED RANGE: $currentCol='.$currentCol.' $currentRow='.$currentRow.'<br />';
                    $cellValue = null;
                    if ($pSheet->cellExists($reference)) {
                        $returnValue[$currentRow][$currentCol] = $pSheet->getCell($reference)->getCalculatedValue($resetLog);
                    } else {
                        $returnValue[$currentRow][$currentCol] = null;
                    }
                }
            }
            // print_r($returnValue);
            // echo '<br />';
        }
        
        return $returnValue;
    }
    
    /**
     * Is a specific function implemented?
     *
     * @param string $pFunction
     *            Function Name
     * @return boolean
     */
    public function isImplemented($pFunction = '') {
        $pFunction = strtoupper($pFunction);
        if (isset(self::$PHPExcelFunctions[$pFunction])) {
            return (self::$PHPExcelFunctions[$pFunction]['functionCall'] != 'Calculation\Categories::DUMMY');
        } else {
            return false;
        }
    }
    
    /**
     * Get a list of all implemented functions as an array of function objects
     *
     * @return array of Calculation\Categories
     */
    public function listFunctions() {
        $returnValue = array();
        
        foreach ( self::$PHPExcelFunctions as $functionName => $function ) {
            if ($function['functionCall'] != 'Calculation\Categories::DUMMY') {
                $returnValue[$functionName] = new Calculation\Categories($function['category'], $functionName, $function['functionCall']);
            }
        }
        
        return $returnValue;
    }
    
    /**
     * Get a list of all Excel function names
     *
     * @return array
     */
    public function listAllFunctionNames() {
        return array_keys(self::$PHPExcelFunctions);
    }
    
    /**
     * Get a list of implemented Excel function names
     *
     * @return array
     */
    public function listFunctionNames() {
        $returnValue = array();
        foreach ( self::$PHPExcelFunctions as $functionName => $function ) {
            if ($function['functionCall'] != 'Calculation\Categories::DUMMY') {
                $returnValue[] = $functionName;
            }
        }
        
        return $returnValue;
    }
}
